Return JsonArray and JsonObject by value (closes #309)

CHANGELOG.md

@@ -1,6 +1,36 @@
 ArduinoJson: change log
 =======================
 
+HEAD
+----
+
+* Return `JsonArray` and `JsonObject` by value instead of reference (issue #309)
+* Replaced `success()` with `isNull()`
+
+> ### BREAKING CHANGES
+> 
+> Old code:
+>
+> ```c++
+> JsonObject& obj = doc.to<JsonObject>();
+> JsonArray& arr = obj.createNestedArray("key");
+> if (!arr.success()) {
+>   Serial.println("No enough memory");
+>   return;
+> }
+> ```
+> 
+> New code:
+> 
+> ```c++
+> JsonObject obj = doc.to<JsonObject>();
+> JsonArray arr = obj.createNestedArray("key");
+> if (arr.isNull()) {
+>   Serial.println("No enough memory");
+>   return;
+> }
+> ```
+
 v6.0.1-beta
 -----------
 

README.md

@@ -63,7 +63,7 @@ char json[] = "{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302
 DynamicJsonDocument doc;
 deserializeJson(doc, json);
 
-JsonObject& root = doc.as<JsonObject>();
+JsonObjectRef root = doc.as<JsonObject>();
 const char* sensor = root["sensor"];
 long time          = root["time"];
 double latitude    = root["data"][0];
@@ -79,11 +79,11 @@ Here is a program that generates a JSON document with ArduinoJson:
 ```c++
 DynamicJsonDocument doc;
 
-JsonObject& root = doc.to<JsonObject>();
+JsonObject root = doc.to<JsonObject>();
 root["sensor"] = "gps";
 root["time"] = 1351824120;
 
-JsonArray& data = root.createNestedArray("data");
+JsonArray data = root.createNestedArray("data");
 data.add(48.756080);
 data.add(2.302038);
 

examples/JsonConfigFile/JsonConfigFile.ino

@@ -40,7 +40,7 @@ void loadConfiguration(const char *filename, Config &config) {
     Serial.println(F("Failed to read file, using default configuration"));
 
   // Get the root object in the document
-  JsonObject &root = doc.as<JsonObject>();
+  JsonObject root = doc.as<JsonObject>();
 
   // Copy values from the JsonObject to the Config
   config.port = root["port"] | 2731;
@@ -70,7 +70,7 @@ void saveConfiguration(const char *filename, const Config &config) {
   StaticJsonDocument<256> doc;
 
   // Make our document contain an object
-  JsonObject &root = doc.to<JsonObject>();
+  JsonObject root = doc.to<JsonObject>();
 
   // Set the values in the object
   root["hostname"] = config.hostname;
@@ -132,15 +132,4 @@ void loop() {
   // not used in this example
 }
 
-// See also
+// Visit https://arduinojson.org/v6/example/config/ for more.
-// --------
-//
-// The website arduinojson.org contains the documentation for all the functions
-// used above. It also includes an FAQ that will help you solve any
-// serialization or deserialization problem.
-// Please check it out at: https://arduinojson.org/
-//
-// The book "Mastering ArduinoJson" contains a case study of a project that has
-// a complex configuration with nested members.
-// Contrary to this example, the project in the book uses the SPIFFS filesystem.
-// Please check it out at: https://arduinojson.org/book/

examples/JsonGeneratorExample/JsonGeneratorExample.ino

@@ -24,7 +24,7 @@ void setup() {
   // DynamicJsonDocument  doc(200);
 
   // Make our document be an object
-  JsonObject& root = doc.to<JsonObject>();
+  JsonObject root = doc.to<JsonObject>();
 
   // Add values in the object
   //
@@ -35,7 +35,7 @@ void setup() {
 
   // Add an array.
   //
-  JsonArray& data = root.createNestedArray("data");
+  JsonArray data = root.createNestedArray("data");
   data.add(48.756080);
   data.add(2.302038);
 
@@ -61,15 +61,4 @@ void loop() {
   // not used in this example
 }
 
-// See also
+// Visit https://arduinojson.org/v6/example/generator/ for more.
-// --------
-//
-// The website arduinojson.org contains the documentation for all the functions
-// used above. It also includes an FAQ that will help you solve any
-// serialization problem.
-// Please check it out at: https://arduinojson.org/
-//
-// The book "Mastering ArduinoJson" contains a tutorial on serialization.
-// It begins with a simple example, like the one above, and then adds more
-// features like serializing directly to a file or an HTTP request.
-// Please check it out at: https://arduinojson.org/book/

examples/JsonHttpClient/JsonHttpClient.ino

@@ -84,7 +84,7 @@ void setup() {
   }
 
   // Extract values
-  JsonObject& root = doc.as<JsonObject>();
+  JsonObject root = doc.as<JsonObject>();
   Serial.println(F("Response:"));
   Serial.println(root["sensor"].as<char*>());
   Serial.println(root["time"].as<char*>());
@@ -99,16 +99,4 @@ void loop() {
   // not used in this example
 }
 
-// See also
+// Visit https://arduinojson.org/v6/example/http-client/ for more.
-// --------
-//
-// The website arduinojson.org contains the documentation for all the functions
-// used above. It also includes an FAQ that will help you solve any
-// serialization  problem.
-// Please check it out at: https://arduinojson.org/
-//
-// The book "Mastering ArduinoJson" contains a tutorial on deserialization
-// showing how to parse the response from Yahoo Weather. In the last chapter,
-// it shows how to parse the huge documents from OpenWeatherMap
-// and Weather Underground.
-// Please check it out at: https://arduinojson.org/book/

examples/JsonParserExample/JsonParserExample.ino

@@ -42,7 +42,7 @@ void setup() {
   }
 
   // Get the root object in the document
-  JsonObject& root = doc.as<JsonObject>();
+  JsonObject root = doc.as<JsonObject>();
 
   // Fetch values.
   //
@@ -64,15 +64,4 @@ void loop() {
   // not used in this example
 }
 
-// See also
+// Visit https://arduinojson.org/v6/example/parser/ for more.
-// --------
-//
-// The website arduinojson.org contains the documentation for all the functions
-// used above. It also includes an FAQ that will help you solve any
-// deserialization problem.
-// Please check it out at: https://arduinojson.org/
-//
-// The book "Mastering ArduinoJson" contains a tutorial on deserialization.
-// It begins with a simple example, like the one above, and then adds more
-// features like deserializing directly from a file or an HTTP request.
-// Please check it out at: https://arduinojson.org/book/

examples/JsonServer/JsonServer.ino

@@ -56,10 +56,10 @@ void loop() {
   StaticJsonDocument<500> doc;
 
   // Make our document represent an object
-  JsonObject& root = doc.to<JsonObject>();
+  JsonObject root = doc.to<JsonObject>();
 
   // Create the "analog" array
-  JsonArray& analogValues = root.createNestedArray("analog");
+  JsonArray analogValues = root.createNestedArray("analog");
   for (int pin = 0; pin < 6; pin++) {
     // Read the analog input
     int value = analogRead(pin);
@@ -69,7 +69,7 @@ void loop() {
   }
 
   // Create the "digital" array
-  JsonArray& digitalValues = root.createNestedArray("digital");
+  JsonArray digitalValues = root.createNestedArray("digital");
   for (int pin = 0; pin < 14; pin++) {
     // Read the digital input
     int value = digitalRead(pin);
@@ -95,15 +95,4 @@ void loop() {
   client.stop();
 }
 
-// See also
+// Visit https://arduinojson.org/v6/example/http-server/ for more.
-// --------
-//
-// The website arduinojson.org contains the documentation for all the functions
-// used above. It also includes an FAQ that will help you solve any
-// serialization problem.
-// Please check it out at: https://arduinojson.org/
-//
-// The book "Mastering ArduinoJson" contains a tutorial on serialization.
-// It begins with a simple example, then adds more features like serializing
-// directly to a file or an HTTP client.
-// Please check it out at: https://arduinojson.org/book/

examples/JsonUdpBeacon/JsonUdpBeacon.ino

@@ -48,10 +48,10 @@ void loop() {
   StaticJsonDocument<500> doc;
 
   // Make our document represent an object
-  JsonObject& root = doc.to<JsonObject>();
+  JsonObject root = doc.to<JsonObject>();
 
   // Create the "analog" array
-  JsonArray& analogValues = root.createNestedArray("analog");
+  JsonArray analogValues = root.createNestedArray("analog");
   for (int pin = 0; pin < 6; pin++) {
     // Read the analog input
     int value = analogRead(pin);
@@ -61,7 +61,7 @@ void loop() {
   }
 
   // Create the "digital" array
-  JsonArray& digitalValues = root.createNestedArray("digital");
+  JsonArray digitalValues = root.createNestedArray("digital");
   for (int pin = 0; pin < 14; pin++) {
     // Read the digital input
     int value = digitalRead(pin);
@@ -87,15 +87,4 @@ void loop() {
   delay(10000);
 }
 
-// See also
+// Visit https://arduinojson.org/v6/example/udp-beacon/ for more.
-// --------
-//
-// The website arduinojson.org contains the documentation for all the functions
-// used above. It also includes an FAQ that will help you solve any
-// serialization problem.
-// Please check it out at: https://arduinojson.org/
-//
-// The book "Mastering ArduinoJson" contains a tutorial on serialization.
-// It begins with a simple example, then adds more features like serializing
-// directly to a file or any stream.
-// Please check it out at: https://arduinojson.org/book/

examples/MsgPackParser/MsgPackParser.ino

@@ -55,7 +55,7 @@ void setup() {
   }
 
   // Get the root object in the document
-  JsonObject& root = doc.as<JsonObject>();
+  JsonObject root = doc.as<JsonObject>();
 
   // Fetch values.
   //
@@ -77,15 +77,4 @@ void loop() {
   // not used in this example
 }
 
-// See also
+// Visit https://arduinojson.org/v6/example/msgpack-parser/ for more.
-// --------
-//
-// The website arduinojson.org contains the documentation for all the functions
-// used above. It also includes an FAQ that will help you solve any
-// deserialization problem.
-// Please check it out at: https://arduinojson.org/
-//
-// The book "Mastering ArduinoJson" contains a tutorial on deserialization.
-// It begins with a simple example, like the one above, and then adds more
-// features like deserializing directly from a file or an HTTP request.
-// Please check it out at: https://arduinojson.org/book/

examples/ProgmemExample/ProgmemExample.ino

@@ -21,7 +21,7 @@ void setup() {
   // JsonBuffer.
   deserializeJson(doc, F("{\"sensor\":\"gps\",\"time\":1351824120,"
                          "\"data\":[48.756080,2.302038]}"));
-  JsonObject& obj = doc.as<JsonObject>();
+  JsonObject obj = doc.as<JsonObject>();
 
   // You can use a Flash String to get an element of a JsonObject
   // No duplication is done.
@@ -56,15 +56,4 @@ void loop() {
   // not used in this example
 }
 
-// See also
+// Visit https://arduinojson.org/v6/example/progmem/ for more.
-// --------
-//
-// The website arduinojson.org contains the documentation for all the functions
-// used above. It also includes an FAQ that will help you solve any memory
-// problem.
-// Please check it out at: https://arduinojson.org/
-//
-// The book "Mastering ArduinoJson" contains a quick C++ course that explains
-// how your microcontroller stores strings in memory. It also tells why you
-// should not abuse Flash strings with ArduinoJson.
-// Please check it out at: https://arduinojson.org/book/

examples/StringExample/StringExample.ino

@@ -18,7 +18,7 @@ void setup() {
   String input =
       "{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";
   deserializeJson(doc, input);
-  JsonObject& obj = doc.as<JsonObject>();
+  JsonObject obj = doc.as<JsonObject>();
 
   // You can use a String to get an element of a JsonObject
   // No duplication is done.
@@ -62,14 +62,4 @@ void loop() {
   // not used in this example
 }
 
-// See also
+// Visit https://arduinojson.org/v6/example/string/ for more.
-// --------
-//
-// The website arduinojson.org contains the documentation for all the functions
-// used above. It also includes an FAQ that will help you solve any problem.
-// Please check it out at: https://arduinojson.org/
-//
-// The book "Mastering ArduinoJson" contains a quick C++ course that explains
-// how your microcontroller stores strings in memory. On several occasions, it
-// shows how you can avoid String in your program.
-// Please check it out at: https://arduinojson.org/book/

src/ArduinoJson.hpp

@@ -7,13 +7,20 @@
 #include "ArduinoJson/version.hpp"
 
 #include "ArduinoJson/DynamicJsonDocument.hpp"
+#include "ArduinoJson/StaticJsonDocument.hpp"
+
+#include "ArduinoJson/JsonObjectImpl.hpp"
+
+#include "ArduinoJson/JsonArray.hpp"
+#include "ArduinoJson/JsonObject.hpp"
+
+#include "ArduinoJson/JsonArrayImpl.hpp"
+#include "ArduinoJson/JsonArraySubscript.hpp"
+#include "ArduinoJson/JsonObjectSubscript.hpp"
+#include "ArduinoJson/JsonVariantImpl.hpp"
+
 #include "ArduinoJson/Json/JsonDeserializer.hpp"
 #include "ArduinoJson/Json/JsonSerializer.hpp"
 #include "ArduinoJson/Json/PrettyJsonSerializer.hpp"
 #include "ArduinoJson/MsgPack/MsgPackDeserializer.hpp"
 #include "ArduinoJson/MsgPack/MsgPackSerializer.hpp"
-#include "ArduinoJson/StaticJsonDocument.hpp"
-
-#include "ArduinoJson/JsonArrayImpl.hpp"
-#include "ArduinoJson/JsonObjectImpl.hpp"
-#include "ArduinoJson/JsonVariantImpl.hpp"

src/ArduinoJson/Data/JsonVariantAs.hpp

@@ -19,24 +19,5 @@ struct JsonVariantAs<char*> {
   typedef const char* type;
 };
 
-template <>
+}  // namespace Internals
-struct JsonVariantAs<JsonArray> {
+}  // namespace ArduinoJson
-  typedef JsonArray& type;
-};
-
-template <>
-struct JsonVariantAs<const JsonArray> {
-  typedef const JsonArray& type;
-};
-
-template <>
-struct JsonVariantAs<JsonObject> {
-  typedef JsonObject& type;
-};
-
-template <>
-struct JsonVariantAs<const JsonObject> {
-  typedef const JsonObject& type;
-};
-}
-}

src/ArduinoJson/Data/JsonVariantContent.hpp

@@ -8,20 +8,19 @@
 #include "JsonInteger.hpp"
 
 namespace ArduinoJson {
-
-// Forward declarations
-class JsonArray;
-class JsonObject;
-
 namespace Internals {
+// Forward declarations
+struct JsonArrayData;
+struct JsonObjectData;
+
 // A union that defines the actual content of a JsonVariant.
 // The enum JsonVariantType determines which member is in use.
 union JsonVariantContent {
   JsonFloat asFloat;         // used for double and float
   JsonUInt asInteger;        // used for bool, char, short, int and longs
   const char* asString;      // asString can be null
-  JsonArray* asArray;    // asArray cannot be null
+  JsonArrayData* asArray;    // asArray cannot be null
-  JsonObject* asObject;  // asObject cannot be null
+  JsonObjectData* asObject;  // asObject cannot be null
 };
-}
+}  // namespace Internals
-}
+}  // namespace ArduinoJson

src/ArduinoJson/Data/JsonVariantType.hpp

@@ -5,8 +5,6 @@
 #pragma once
 
 namespace ArduinoJson {
-class JsonArray;
-class JsonObject;
 
 namespace Internals {
 
@@ -19,9 +17,9 @@ enum JsonVariantType {
   JSON_BOOLEAN,           // JsonVariant stores a bool
   JSON_POSITIVE_INTEGER,  // JsonVariant stores an JsonUInt
   JSON_NEGATIVE_INTEGER,  // JsonVariant stores an JsonUInt that must be negated
-  JSON_ARRAY,             // JsonVariant stores a pointer to a JsonArray
+  JSON_ARRAY,             // JsonVariant stores a pointer to a JsonArrayData
-  JSON_OBJECT,            // JsonVariant stores a pointer to a JsonObject
+  JSON_OBJECT,            // JsonVariant stores a pointer to a JsonObjectData
   JSON_FLOAT              // JsonVariant stores a JsonFloat
 };
-}
+}  // namespace Internals
-}
+}  // namespace ArduinoJson

src/ArduinoJson/Data/List.hpp

@@ -13,7 +13,7 @@ namespace Internals {
 
 // A singly linked list of T.
 // The linked list is composed of ListNode<T>.
-// It is derived by JsonArray and JsonObject
+// It is derived by JsonArrayData and JsonObjectData
 template <typename T>
 class List {
  public:
@@ -22,23 +22,10 @@ class List {
   typedef ListIterator<T> iterator;
   typedef ListConstIterator<T> const_iterator;
 
-  // Creates an empty List<T> attached to a JsonBuffer.
-  // The JsonBuffer allows to allocate new nodes.
-  // When buffer is NULL, the List is not able to grow and success() returns
-  // false. This is used to identify bad memory allocations and parsing
-  // failures.
   explicit List(JsonBuffer *buf) : _buffer(buf), _firstNode(NULL) {}
 
-  // Returns true if the object is valid
-  // Would return false in the following situation:
-  // - the memory allocation failed (StaticJsonBuffer was too small)
-  // - the JSON parsing failed
-  bool success() const {
-    return _buffer != NULL;
-  }
-
   // Returns the numbers of elements in the list.
-  // For a JsonObject, it would return the number of key-value pairs
+  // For a JsonObjectData, it would return the number of key-value pairs
   size_t size() const {
     size_t nodeCount = 0;
     for (node_type *node = _firstNode; node; node = node->next) nodeCount++;
@@ -87,14 +74,13 @@ class List {
   JsonBuffer &buffer() const {
     return *_buffer;
   }
+  JsonBuffer *_buffer;  // TODO!!
 
  protected:
   void clear() {
     _firstNode = 0;
   }
 
-  JsonBuffer *_buffer;
-
  private:
   node_type *_firstNode;
 };

src/ArduinoJson/Data/ReferenceType.hpp

@@ -1,24 +0,0 @@
-// ArduinoJson - arduinojson.org
-// Copyright Benoit Blanchon 2014-2018
-// MIT License
-
-#pragma once
-
-namespace ArduinoJson {
-namespace Internals {
-
-// A type that is meant to be used by reference only (JsonArray and JsonObject)
-class ReferenceType {
- public:
-  bool operator==(const ReferenceType& other) const {
-    // two JsonArray are equal if they are the same instance
-    // (we don't compare the content)
-    return this == &other;
-  }
-
-  bool operator!=(const ReferenceType& other) const {
-    return this != &other;
-  }
-};
-}
-}

src/ArduinoJson/DynamicJsonDocument.hpp

@@ -32,28 +32,26 @@ class DynamicJsonDocument {
     return _root.as<T>();
   }
 
-  // JsonObject& to<JsonObject>()
+  // JsonObject to<JsonObject>()
   template <typename T>
   typename Internals::enable_if<Internals::is_same<T, JsonObject>::value,
-                                JsonObject&>::type
+                                JsonObject>::type
   to() {
     clear();
-    JsonObject* object = new (&_buffer) JsonObject(&_buffer);
+    JsonObject object(&_buffer);
-    if (!object) return JsonObject::invalid();
     _root = object;
-    return *object;
+    return object;
   }
 
-  // JsonArray& to<JsonArray>()
+  // JsonArray to<JsonArray>()
   template <typename T>
   typename Internals::enable_if<Internals::is_same<T, JsonArray>::value,
-                                JsonArray&>::type
+                                JsonArray>::type
   to() {
     clear();
-    JsonArray* array = new (&_buffer) JsonArray(&_buffer);
+    JsonArray array(&_buffer);
-    if (!array) return JsonArray::invalid();
     _root = array;
-    return *array;
+    return array;
   }
 
   // JsonVariant& to<JsonVariant>()

src/ArduinoJson/Json/JsonDeserializer.hpp

@@ -66,8 +66,8 @@ class JsonDeserializer {
   DeserializationError parseArray(JsonVariant &variant) {
     if (_nestingLimit == 0) return DeserializationError::TooDeep;
 
-    JsonArray *array = new (_buffer) JsonArray(_buffer);
+    JsonArray array(_buffer);
-    if (!array) return DeserializationError::NoMemory;
+    if (array.isNull()) return DeserializationError::NoMemory;
     variant = array;
 
     // Check opening braket
@@ -88,7 +88,7 @@ class JsonDeserializer {
       err = parse(value);
       _nestingLimit++;
       if (err) return err;
-      if (!array->add(value)) return DeserializationError::NoMemory;
+      if (!array.add(value)) return DeserializationError::NoMemory;
 
       // 2 - Skip spaces
       err = skipSpacesAndComments();
@@ -103,8 +103,8 @@ class JsonDeserializer {
   DeserializationError parseObject(JsonVariant &variant) {
     if (_nestingLimit == 0) return DeserializationError::TooDeep;
 
-    JsonObject *object = new (_buffer) JsonObject(_buffer);
+    JsonObject object(_buffer);
-    if (!object) return DeserializationError::NoMemory;
+    if (object.isNull()) return DeserializationError::NoMemory;
     variant = object;
 
     // Check opening brace
@@ -126,9 +126,7 @@ class JsonDeserializer {
 
       // Skip spaces
       err = skipSpacesAndComments();
-      if (err) return err;
+      if (err) return err;  // Colon
-
-      // Colon
       if (!eat(':')) return DeserializationError::InvalidInput;
 
       // Parse value
@@ -137,7 +135,7 @@ class JsonDeserializer {
       err = parse(value);
       _nestingLimit++;
       if (err) return err;
-      if (!object->set(key, value)) return DeserializationError::NoMemory;
+      if (!object.set(key, value)) return DeserializationError::NoMemory;
 
       // Skip spaces
       err = skipSpacesAndComments();

src/ArduinoJson/Json/JsonSerializer.hpp

@@ -75,7 +75,9 @@ class JsonSerializer {
     _writer.writeBoolean(value);
   }
 
-  void acceptUndefined() {}
+  void acceptNull() {
+    _writer.writeRaw("null");
+  }
 
   size_t bytesWritten() const {
     return _writer.bytesWritten();

src/ArduinoJson/Json/JsonWriter.hpp

@@ -13,13 +13,6 @@
 namespace ArduinoJson {
 namespace Internals {
 
-// Writes the JSON tokens to a Print implementation
-// This class is used by:
-// - JsonArray::writeTo()
-// - JsonObject::writeTo()
-// - JsonVariant::writeTo()
-// Its derived by PrettyJsonWriter that overrides some members to add
-// indentation.
 template <typename Print>
 class JsonWriter {
  public:

src/ArduinoJson/JsonArray.hpp

@@ -4,47 +4,33 @@
 
 #pragma once
 
-#include "Data/List.hpp"
+#include "./JsonArrayData.hpp"
-#include "Data/ReferenceType.hpp"
-#include "Data/ValueSaver.hpp"
-#include "JsonVariant.hpp"
-#include "Memory/JsonBufferAllocated.hpp"
-#include "Polyfills/type_traits.hpp"
-#include "Strings/StringTraits.hpp"
-
-// Returns the size (in bytes) of an array with n elements.
-// Can be very handy to determine the size of a StaticJsonBuffer.
-#define JSON_ARRAY_SIZE(NUMBER_OF_ELEMENTS) \
-  (sizeof(JsonArray) + (NUMBER_OF_ELEMENTS) * sizeof(JsonArray::node_type))
 
 namespace ArduinoJson {
 
-// Forward declarations
 class JsonObject;
-class JsonBuffer;
+
 namespace Internals {
 class JsonArraySubscript;
 }
 
-class JsonArray : public Internals::ReferenceType,
+class JsonArray {
-                  public Internals::NonCopyable,
+  friend class JsonVariant;
-                  public Internals::List<JsonVariant>,
+
-                  public Internals::JsonBufferAllocated {
  public:
-  explicit JsonArray(Internals::JsonBuffer *buf) throw()
+  typedef Internals::JsonArrayData::iterator iterator;
-      : Internals::List<JsonVariant>(buf) {}
+  typedef Internals::JsonArrayData::const_iterator const_iterator;
 
-  // Gets the value at the specified index
+  JsonArray() : _data(0) {}
-  const Internals::JsonArraySubscript operator[](size_t index) const;
+  JsonArray(Internals::JsonArrayData* arr) : _data(arr) {}
-
+  JsonArray(Internals::JsonBuffer* buf)
-  // Gets or sets the value at specified index
+      : _data(new (buf) Internals::JsonArrayData(buf)) {}
-  Internals::JsonArraySubscript operator[](size_t index);
 
   // Adds the specified value at the end of the array.
   //
   // bool add(TValue);
   // TValue = bool, long, int, short, float, double, RawJson, JsonVariant,
-  //          std::string, String, JsonArray, JsonObject
+  //          std::string, String, JsonArrayData, JsonObject
   template <typename T>
   bool add(const T& value) {
     return add_impl<const T&>(value);
@@ -56,73 +42,23 @@ class JsonArray : public Internals::ReferenceType,
   bool add(T* value) {
     return add_impl<T*>(value);
   }
-  //
+
-  // bool add(TValue value, uint8_t decimals);
+  iterator begin() {
-  // TValue = float, double
+    if (!_data) return iterator();
-  template <typename T>
+    return _data->begin();
-  DEPRECATED("Second argument is not supported anymore")
-  bool add(T value, uint8_t) {
-    return add_impl<const JsonVariant &>(JsonVariant(value));
   }
 
-  // Sets the value at specified index.
+  const_iterator begin() const {
-  //
+    if (!_data) return const_iterator();
-  // bool add(size_t index, const TValue&);
+    return _data->begin();
-  // TValue = bool, long, int, short, float, double, RawJson, JsonVariant,
-  //          std::string, String, JsonArray, JsonObject
-  template <typename T>
-  bool set(size_t index, const T &value) {
-    return set_impl<const T &>(index, value);
-  }
-  //
-  // bool add(size_t index, TValue);
-  // TValue = char*, const char*, const FlashStringHelper*
-  template <typename T>
-  bool set(size_t index, T *value) {
-    return set_impl<T *>(index, value);
-  }
-  //
-  // bool set(size_t index, TValue value, uint8_t decimals);
-  // TValue = float, double
-  template <typename T>
-  typename Internals::enable_if<Internals::is_floating_point<T>::value,
-                                bool>::type
-  set(size_t index, T value, uint8_t decimals) {
-    return set_impl<const JsonVariant &>(index, JsonVariant(value, decimals));
   }
 
-  // Gets the value at the specified index.
+  iterator end() {
-  template <typename T>
+    return iterator();
-  typename Internals::JsonVariantAs<T>::type get(size_t index) const {
-    const_iterator it = begin() += index;
-    return it != end() ? it->as<T>() : Internals::JsonVariantDefault<T>::get();
   }
 
-  // Check the type of the value at specified index.
+  const_iterator end() const {
-  template <typename T>
+    return const_iterator();
-  bool is(size_t index) const {
-    const_iterator it = begin() += index;
-    return it != end() ? it->is<T>() : false;
-  }
-
-  // Creates a JsonArray and adds a reference at the end of the array.
-  JsonArray &createNestedArray();
-
-  // Creates a JsonObject and adds a reference at the end of the array.
-  JsonObject &createNestedObject();
-
-  // Removes element at specified index.
-  void remove(size_t index) {
-    remove(begin() += index);
-  }
-  using Internals::List<JsonVariant>::remove;
-
-  // Returns a reference an invalid JsonArray.
-  // This object is meant to replace a NULL pointer.
-  // This is used when memory allocation or JSON parsing fail.
-  static JsonArray &invalid() {
-    static JsonArray instance(NULL);
-    return instance;
   }
 
   // Imports a 1D array
@@ -146,7 +82,7 @@ class JsonArray : public Internals::ReferenceType,
   bool copyFrom(T (&array)[N1][N2]) {
     bool ok = true;
     for (size_t i = 0; i < N1; i++) {
-      JsonArray &nestedArray = createNestedArray();
+      JsonArray nestedArray = createNestedArray();
       for (size_t j = 0; j < N2; j++) {
         ok &= nestedArray.add(array[i][j]);
       }
@@ -172,15 +108,83 @@ class JsonArray : public Internals::ReferenceType,
   // Exports a 2D array
   template <typename T, size_t N1, size_t N2>
   void copyTo(T (&array)[N1][N2]) const {
+    if (!_data) return;
     size_t i = 0;
     for (const_iterator it = begin(); it != end() && i < N1; ++it) {
       it->as<JsonArray>().copyTo(array[i++]);
     }
   }
 
+  JsonArray createNestedArray();
+  JsonObject createNestedObject();
+
+  Internals::JsonArraySubscript operator[](size_t index);
+
+  const Internals::JsonArraySubscript operator[](size_t index) const;
+
+  bool operator==(const JsonArray& rhs) const {
+    return _data == rhs._data;
+  }
+
+  // Gets the value at the specified index.
+  template <typename T>
+  typename Internals::JsonVariantAs<T>::type get(size_t index) const {
+    const_iterator it = begin() += index;
+    return it != end() ? it->as<T>() : Internals::JsonVariantDefault<T>::get();
+  }
+
+  // Check the type of the value at specified index.
+  template <typename T>
+  bool is(size_t index) const {
+    const_iterator it = begin() += index;
+    return it != end() ? it->is<T>() : false;
+  }
+
+  // Removes element at specified position.
+  void remove(iterator it) {
+    if (!_data) return;
+    _data->remove(it);
+  }
+
+  // Removes element at specified index.
+  void remove(size_t index) {
+    remove(begin() += index);
+  }
+
+  // Sets the value at specified index.
+  //
+  // bool add(size_t index, const TValue&);
+  // TValue = bool, long, int, short, float, double, RawJson, JsonVariant,
+  //          std::string, String, JsonArrayData, JsonObject
+  template <typename T>
+  bool set(size_t index, const T& value) {
+    if (!_data) return false;
+    return set_impl<const T&>(index, value);
+  }
+  //
+  // bool add(size_t index, TValue);
+  // TValue = char*, const char*, const FlashStringHelper*
+  template <typename T>
+  bool set(size_t index, T* value) {
+    if (!_data) return false;
+    return set_impl<T*>(index, value);
+  }
+
+  size_t size() const {
+    if (!_data) return 0;
+    return _data->size();
+  }
+
+  bool isNull() const {
+    return _data == 0;
+  }
+
   template <typename Visitor>
   void visit(Visitor& visitor) const {
+    if (_data)
       return visitor.acceptArray(*this);
+    else
+      visitor.acceptNull();
   }
 
  private:
@@ -188,23 +192,17 @@ class JsonArray : public Internals::ReferenceType,
   bool set_impl(size_t index, TValueRef value) {
     iterator it = begin() += index;
     if (it == end()) return false;
-    return Internals::ValueSaver<TValueRef>::save(_buffer, *it, value);
+    return Internals::ValueSaver<TValueRef>::save(_data->_buffer, *it, value);
   }
 
   template <typename TValueRef>
   bool add_impl(TValueRef value) {
-    iterator it = Internals::List<JsonVariant>::add();
+    if (!_data) return false;
+    iterator it = _data->add();
     if (it == end()) return false;
-    return Internals::ValueSaver<TValueRef>::save(_buffer, *it, value);
+    return Internals::ValueSaver<TValueRef>::save(_data->_buffer, *it, value);
   }
-};
 
-namespace Internals {
+  Internals::JsonArrayData* _data;
-template <>
-struct JsonVariantDefault<JsonArray> {
-  static JsonArray &get() {
-    return JsonArray::invalid();
-  }
 };
-}  // namespace Internals
 }  // namespace ArduinoJson

src/ArduinoJson/JsonArrayData.hpp

@@ -0,0 +1,27 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#pragma once
+
+#include "Data/List.hpp"
+#include "Data/ValueSaver.hpp"
+#include "JsonVariant.hpp"
+#include "Memory/JsonBufferAllocated.hpp"
+#include "Polyfills/type_traits.hpp"
+#include "Strings/StringTraits.hpp"
+
+// Returns the size (in bytes) of an array with n elements.
+// Can be very handy to determine the size of a StaticJsonBuffer.
+#define JSON_ARRAY_SIZE(NUMBER_OF_ELEMENTS)        \
+  (sizeof(ArduinoJson::Internals::JsonArrayData) + \
+   (NUMBER_OF_ELEMENTS) *                          \
+       sizeof(ArduinoJson::Internals::JsonArrayData::node_type))
+
+namespace ArduinoJson {
+namespace Internals {
+struct JsonArrayData : List<JsonVariant>, JsonBufferAllocated {
+  explicit JsonArrayData(JsonBuffer *buf) throw() : List<JsonVariant>(buf) {}
+};
+}  // namespace Internals
+}  // namespace ArduinoJson

src/ArduinoJson/JsonArrayImpl.hpp

@@ -5,24 +5,21 @@
 #pragma once
 
 #include "JsonArray.hpp"
-#include "JsonArraySubscript.hpp"
 #include "JsonObject.hpp"
 
 namespace ArduinoJson {
 
-inline JsonArray &JsonArray::createNestedArray() {
+inline JsonArray JsonArray::createNestedArray() {
-  JsonArray *array = new (_buffer) JsonArray(_buffer);
+  if (!_data) return JsonArray();
-  if (!array) return JsonArray::invalid();
+  JsonArray array(_data->_buffer);
-
+  if (!array.isNull()) add(array);
-  add(array);
+  return array;
-  return *array;
 }
 
-inline JsonObject &JsonArray::createNestedObject() {
+inline JsonObject JsonArray::createNestedObject() {
-  JsonObject *object = new (_buffer) JsonObject(_buffer);
+  if (!_data) return JsonObject();
-  if (!object) return JsonObject::invalid();
+  JsonObject object(_data->_buffer);
-
+  if (!object.isNull()) add(object);
-  add(object);
+  return object;
-  return *object;
 }
 }  // namespace ArduinoJson

src/ArduinoJson/JsonArraySubscript.hpp

@@ -16,7 +16,7 @@ namespace ArduinoJson {
 namespace Internals {
 class JsonArraySubscript : public JsonVariantBase<JsonArraySubscript> {
  public:
-  FORCE_INLINE JsonArraySubscript(JsonArray& array, size_t index)
+  FORCE_INLINE JsonArraySubscript(JsonArray array, size_t index)
       : _array(array), _index(index) {}
 
   FORCE_INLINE JsonArraySubscript& operator=(const JsonArraySubscript& src) {
@@ -43,8 +43,8 @@ class JsonArraySubscript : public JsonVariantBase<JsonArraySubscript> {
     return *this;
   }
 
-  FORCE_INLINE bool success() const {
+  FORCE_INLINE bool isNull() const {
-    return _index < _array.size();
+    return _index >= _array.size();
   }
 
   template <typename T>
@@ -80,7 +80,7 @@ class JsonArraySubscript : public JsonVariantBase<JsonArraySubscript> {
   }
 
  private:
-  JsonArray& _array;
+  JsonArray _array;
   const size_t _index;
 };
 
@@ -103,7 +103,7 @@ inline Internals::JsonArraySubscript JsonArray::operator[](size_t index) {
 
 inline const Internals::JsonArraySubscript JsonArray::operator[](
     size_t index) const {
-  return Internals::JsonArraySubscript(*const_cast<JsonArray*>(this), index);
+  return Internals::JsonArraySubscript(*this, index);
 }
 }  // namespace ArduinoJson
 

src/ArduinoJson/JsonObject.hpp

@@ -4,110 +4,82 @@
 
 #pragma once
 
-#include "Data/List.hpp"
+#include "./JsonObjectData.hpp"
-#include "Data/ReferenceType.hpp"
-#include "Data/ValueSaver.hpp"
-#include "JsonPair.hpp"
-#include "Memory/JsonBufferAllocated.hpp"
-#include "Polyfills/type_traits.hpp"
-#include "Strings/StringTraits.hpp"
-
-// Returns the size (in bytes) of an object with n elements.
-// Can be very handy to determine the size of a StaticJsonBuffer.
-#define JSON_OBJECT_SIZE(NUMBER_OF_ELEMENTS) \
-  (sizeof(JsonObject) + (NUMBER_OF_ELEMENTS) * sizeof(JsonObject::node_type))
 
 namespace ArduinoJson {
 
-// Forward declarations
+class JsonObject {
-class JsonArray;
+  friend class JsonVariant;
-class JsonBuffer;
-namespace Internals {
-template <typename>
-class JsonObjectSubscript;
-}
 
-class JsonObject : public Internals::ReferenceType,
-                   public Internals::NonCopyable,
-                   public Internals::List<JsonPair>,
-                   public Internals::JsonBufferAllocated {
  public:
-  // Create an empty JsonArray attached to the specified JsonBuffer.
+  typedef Internals::JsonObjectData::iterator iterator;
-  // You should not use this constructor directly.
+  typedef Internals::JsonObjectData::const_iterator const_iterator;
-  explicit JsonObject(Internals::JsonBuffer* buf) throw()
-      : Internals::List<JsonPair>(buf) {}
 
-  // Gets or sets the value associated with the specified key.
+  JsonObject() : _data(0) {}
-  //
+  JsonObject(Internals::JsonObjectData* object) : _data(object) {}
-  // JsonObjectSubscript operator[](TKey)
+  JsonObject(Internals::JsonBuffer* buf)
-  // TKey = const std::string&, const String&
+      : _data(new (buf) Internals::JsonObjectData(buf)) {}
-  template <typename TString>
+
-  Internals::JsonObjectSubscript<const TString&> operator[](
+  iterator begin() {
-      const TString& key) {
+    if (!_data) return iterator();
-    return Internals::JsonObjectSubscript<const TString&>(*this, key);
+    return _data->begin();
-  }
-  //
-  // JsonObjectSubscript operator[](TKey)
-  // TKey = char*, const char*, char[], const char[N], const FlashStringHelper*
-  template <typename TString>
-  Internals::JsonObjectSubscript<TString*> operator[](TString* key) {
-    return Internals::JsonObjectSubscript<TString*>(*this, key);
   }
 
-  // Gets the value associated with the specified key.
+  const_iterator begin() const {
-  //
+    if (!_data) return const_iterator();
-  // const JsonObjectSubscript operator[](TKey) const;
+    return _data->begin();
-  // TKey = const std::string&, const String&
-  template <typename TString>
-  const Internals::JsonObjectSubscript<const TString&> operator[](
-      const TString& key) const {
-    return Internals::JsonObjectSubscript<const TString&>(
-        *const_cast<JsonObject*>(this), key);
-  }
-  //
-  // const JsonObjectSubscript operator[](TKey) const;
-  // TKey = const char*, const char[N], const FlashStringHelper*
-  template <typename TString>
-  const Internals::JsonObjectSubscript<TString*> operator[](
-      TString* key) const {
-    return Internals::JsonObjectSubscript<TString*>(
-        *const_cast<JsonObject*>(this), key);
   }
 
-  // Sets the specified key with the specified value.
+  // Tells weither the specified key is present and associated with a value.
   //
-  // bool set(TKey, TValue);
+  // bool containsKey(TKey);
   // TKey = const std::string&, const String&
-  // TValue = bool, long, int, short, float, double, RawJson, JsonVariant,
+  template <typename TString>
-  //          std::string, String, JsonArray, JsonObject
+  bool containsKey(const TString& key) const {
-  template <typename TValue, typename TString>
+    return containsKey_impl<const TString&>(key);
-  bool set(const TString& key, const TValue& value) {
-    return set_impl<const TString&, const TValue&>(key, value);
   }
   //
-  // bool set(TKey, TValue);
+  // bool containsKey(TKey);
+  // TKey = char*, const char*, char[], const char[], const FlashStringHelper*
+  template <typename TString>
+  bool containsKey(TString* key) const {
+    return containsKey_impl<TString*>(key);
+  }
+
+  iterator end() {
+    return iterator();
+  }
+
+  const_iterator end() const {
+    return const_iterator();
+  }
+
+  // Creates and adds a JsonArray.
+  //
+  // JsonArray createNestedArray(TKey);
   // TKey = const std::string&, const String&
-  // TValue = char*, const char*, const FlashStringHelper*
+  template <typename TString>
-  template <typename TValue, typename TString>
+  JsonArray createNestedArray(const TString& key);
-  bool set(const TString& key, TValue* value) {
+  // JsonArray createNestedArray(TKey);
-    return set_impl<const TString&, TValue*>(key, value);
+  // TKey = char*, const char*, char[], const char[], const FlashStringHelper*
+  template <typename TString>
+  JsonArray createNestedArray(TString* key);
+
+  // Creates and adds a JsonObject.
+  //
+  // JsonObject createNestedObject(TKey);
+  // TKey = const std::string&, const String&
+  template <typename TString>
+  JsonObject createNestedObject(const TString& key) {
+    if (!_data) return JsonObject();
+    return createNestedObject_impl<const TString&>(key);
   }
   //
-  // bool set(TKey, const TValue&);
+  // JsonObject createNestedObject(TKey);
-  // TKey = char*, const char*, const FlashStringHelper*
+  // TKey = char*, const char*, char[], const char[], const FlashStringHelper*
-  // TValue = bool, long, int, short, float, double, RawJson, JsonVariant,
+  template <typename TString>
-  //          std::string, String, JsonArray, JsonObject
+  JsonObject createNestedObject(TString* key) {
-  template <typename TValue, typename TString>
+    return createNestedObject_impl<TString*>(key);
-  bool set(TString* key, const TValue& value) {
-    return set_impl<TString*, const TValue&>(key, value);
-  }
-  //
-  // bool set(TKey, TValue);
-  // TKey = char*, const char*, const FlashStringHelper*
-  // TValue = char*, const char*, const FlashStringHelper*
-  template <typename TValue, typename TString>
-  bool set(TString* key, TValue* value) {
-    return set_impl<TString*, TValue*>(key, value);
   }
 
   // Gets the value associated with the specified key.
@@ -152,51 +124,48 @@ class JsonObject : public Internals::ReferenceType,
     return is_impl<TString*, TValue>(key);
   }
 
-  // Creates and adds a JsonArray.
+  // Gets or sets the value associated with the specified key.
   //
-  // JsonArray& createNestedArray(TKey);
+  // JsonObjectSubscript operator[](TKey)
   // TKey = const std::string&, const String&
   template <typename TString>
-  JsonArray& createNestedArray(const TString& key) {
+  Internals::JsonObjectSubscript<const TString&> operator[](
-    return createNestedArray_impl<const TString&>(key);
+      const TString& key) {
+    return Internals::JsonObjectSubscript<const TString&>(*this, key);
   }
-  // JsonArray& createNestedArray(TKey);
+  //
-  // TKey = char*, const char*, char[], const char[], const FlashStringHelper*
+  // JsonObjectSubscript operator[](TKey)
+  // TKey = char*, const char*, char[], const char[N], const FlashStringHelper*
   template <typename TString>
-  JsonArray& createNestedArray(TString* key) {
+  Internals::JsonObjectSubscript<TString*> operator[](TString* key) {
-    return createNestedArray_impl<TString*>(key);
+    return Internals::JsonObjectSubscript<TString*>(*this, key);
   }
 
-  // Creates and adds a JsonObject.
+  // Gets the value associated with the specified key.
   //
-  // JsonObject& createNestedObject(TKey);
+  // const JsonObjectSubscript operator[](TKey) const;
   // TKey = const std::string&, const String&
   template <typename TString>
-  JsonObject& createNestedObject(const TString& key) {
+  const Internals::JsonObjectSubscript<const TString&> operator[](
-    return createNestedObject_impl<const TString&>(key);
+      const TString& key) const {
+    return Internals::JsonObjectSubscript<const TString&>(*this, key);
   }
   //
-  // JsonObject& createNestedObject(TKey);
+  // const JsonObjectSubscript operator[](TKey) const;
-  // TKey = char*, const char*, char[], const char[], const FlashStringHelper*
+  // TKey = const char*, const char[N], const FlashStringHelper*
   template <typename TString>
-  JsonObject& createNestedObject(TString* key) {
+  const Internals::JsonObjectSubscript<TString*> operator[](
-    return createNestedObject_impl<TString*>(key);
+      TString* key) const {
+    return Internals::JsonObjectSubscript<TString*>(*this, key);
   }
 
-  // Tells weither the specified key is present and associated with a value.
+  bool operator==(const JsonObject& rhs) const {
-  //
+    return _data == rhs._data;
-  // bool containsKey(TKey);
-  // TKey = const std::string&, const String&
-  template <typename TString>
-  bool containsKey(const TString& key) const {
-    return findKey<const TString&>(key) != end();
   }
-  //
+
-  // bool containsKey(TKey);
+  void remove(iterator it) {
-  // TKey = char*, const char*, char[], const char[], const FlashStringHelper*
+    if (!_data) return;
-  template <typename TString>
+    _data->remove(it);
-  bool containsKey(TString* key) const {
-    return findKey<TString*>(key) != end();
   }
 
   // Removes the specified key and the associated value.
@@ -205,33 +174,81 @@ class JsonObject : public Internals::ReferenceType,
   // TKey = const std::string&, const String&
   template <typename TString>
   void remove(const TString& key) {
-    remove(findKey<const TString&>(key));
+    remove_impl<const TString&>(key);
   }
   //
   // void remove(TKey);
   // TKey = char*, const char*, char[], const char[], const FlashStringHelper*
   template <typename TString>
   void remove(TString* key) {
-    remove(findKey<TString*>(key));
+    remove_impl<TString*>(key);
+  }
+
+  // Sets the specified key with the specified value.
+  //
+  // bool set(TKey, TValue);
+  // TKey = const std::string&, const String&
+  // TValue = bool, long, int, short, float, double, RawJson, JsonVariant,
+  //          std::string, String, JsonArray, JsonObject
+  template <typename TValue, typename TString>
+  bool set(const TString& key, const TValue& value) {
+    return set_impl<const TString&, const TValue&>(key, value);
   }
   //
-  // void remove(iterator)
+  // bool set(TKey, TValue);
-  using Internals::List<JsonPair>::remove;
+  // TKey = const std::string&, const String&
+  // TValue = char*, const char*, const FlashStringHelper*
+  template <typename TValue, typename TString>
+  bool set(const TString& key, TValue* value) {
+    return set_impl<const TString&, TValue*>(key, value);
+  }
+  //
+  // bool set(TKey, const TValue&);
+  // TKey = char*, const char*, const FlashStringHelper*
+  // TValue = bool, long, int, short, float, double, RawJson, JsonVariant,
+  //          std::string, String, JsonArray, JsonObject
+  template <typename TValue, typename TString>
+  bool set(TString* key, const TValue& value) {
+    return set_impl<TString*, const TValue&>(key, value);
+  }
+  //
+  // bool set(TKey, TValue);
+  // TKey = char*, const char*, const FlashStringHelper*
+  // TValue = char*, const char*, const FlashStringHelper*
+  template <typename TValue, typename TString>
+  bool set(TString* key, TValue* value) {
+    return set_impl<TString*, TValue*>(key, value);
+  }
 
-  // Returns a reference an invalid JsonObject.
+  size_t size() const {
-  // This object is meant to replace a NULL pointer.
+    if (!_data) return 0;
-  // This is used when memory allocation or JSON parsing fail.
+    return _data->size();
-  static JsonObject& invalid() {
+  }
-    static JsonObject instance(NULL);
+
-    return instance;
+  bool isNull() const {
+    return _data == 0;
   }
 
   template <typename Visitor>
   void visit(Visitor& visitor) const {
-    return visitor.acceptObject(*this);
+    if (_data)
+      visitor.acceptObject(*this);
+    else
+      return visitor.acceptNull();
   }
 
  private:
+  template <typename TStringRef>
+  bool containsKey_impl(TStringRef key) const {
+    return findKey<TStringRef>(key) != end();
+  }
+
+  template <typename TStringRef>
+  JsonArray createNestedArray_impl(TStringRef key);
+
+  template <typename TStringRef>
+  JsonObject createNestedObject_impl(TStringRef key);
+
   // Returns the list node that matches the specified key.
   template <typename TStringRef>
   iterator findKey(TStringRef key) {
@@ -254,26 +271,6 @@ class JsonObject : public Internals::ReferenceType,
                        : Internals::JsonVariantDefault<TValue>::get();
   }
 
-  template <typename TStringRef, typename TValueRef>
-  bool set_impl(TStringRef key, TValueRef value) {
-    // ignore null key
-    if (Internals::StringTraits<TStringRef>::is_null(key)) return false;
-
-    // search a matching key
-    iterator it = findKey<TStringRef>(key);
-    if (it == end()) {
-      // add the key
-      it = Internals::List<JsonPair>::add();
-      if (it == end()) return false;
-      bool key_ok =
-          Internals::ValueSaver<TStringRef>::save(_buffer, it->key, key);
-      if (!key_ok) return false;
-    }
-
-    // save the value
-    return Internals::ValueSaver<TValueRef>::save(_buffer, it->value, value);
-  }
-
   template <typename TStringRef, typename TValue>
   bool is_impl(TStringRef key) const {
     const_iterator it = findKey<TStringRef>(key);
@@ -281,18 +278,34 @@ class JsonObject : public Internals::ReferenceType,
   }
 
   template <typename TStringRef>
-  JsonArray& createNestedArray_impl(TStringRef key);
+  void remove_impl(TStringRef key) {
-
+    if (!_data) return;
-  template <typename TStringRef>
+    _data->remove(findKey<TStringRef>(key));
-  JsonObject& createNestedObject_impl(TStringRef key);
-};
-
-namespace Internals {
-template <>
-struct JsonVariantDefault<JsonObject> {
-  static JsonObject& get() {
-    return JsonObject::invalid();
   }
+
+  template <typename TStringRef, typename TValueRef>
+  bool set_impl(TStringRef key, TValueRef value) {
+    if (!_data) return false;
+
+    // ignore null key
+    if (Internals::StringTraits<TStringRef>::is_null(key)) return false;
+
+    // search a matching key
+    iterator it = findKey<TStringRef>(key);
+    if (it == end()) {
+      // add the key
+      it = _data->add();
+      if (it == end()) return false;
+      bool key_ok =
+          Internals::ValueSaver<TStringRef>::save(_data->_buffer, it->key, key);
+      if (!key_ok) return false;
+    }
+
+    // save the value
+    return Internals::ValueSaver<TValueRef>::save(_data->_buffer, it->value,
+                                                  value);
+  }
+
+  Internals::JsonObjectData* _data;
 };
-}  // namespace Internals
 }  // namespace ArduinoJson

src/ArduinoJson/JsonObjectData.hpp

@@ -0,0 +1,27 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#pragma once
+
+#include "Data/List.hpp"
+#include "Data/ValueSaver.hpp"
+#include "JsonPair.hpp"
+#include "Memory/JsonBufferAllocated.hpp"
+#include "Polyfills/type_traits.hpp"
+#include "Strings/StringTraits.hpp"
+
+// Returns the size (in bytes) of an object with n elements.
+// Can be very handy to determine the size of a StaticJsonBuffer.
+#define JSON_OBJECT_SIZE(NUMBER_OF_ELEMENTS)        \
+  (sizeof(ArduinoJson::Internals::JsonObjectData) + \
+   (NUMBER_OF_ELEMENTS) *                           \
+       sizeof(ArduinoJson::Internals::JsonObjectData::node_type))
+
+namespace ArduinoJson {
+namespace Internals {
+struct JsonObjectData : List<JsonPair>, JsonBufferAllocated {
+  explicit JsonObjectData(JsonBuffer* buf) throw() : List<JsonPair>(buf) {}
+};
+}  // namespace Internals
+}  // namespace ArduinoJson

src/ArduinoJson/JsonObjectImpl.hpp

@@ -6,23 +6,32 @@
 
 #include "JsonArray.hpp"
 #include "JsonObject.hpp"
-#include "JsonObjectSubscript.hpp"
 
 namespace ArduinoJson {
 
-template <typename TStringRef>
+template <typename TString>
-inline JsonArray &JsonObject::createNestedArray_impl(TStringRef key) {
+inline JsonArray JsonObject::createNestedArray(const TString& key) {
-  JsonArray *array = new (_buffer) JsonArray(_buffer);
+  return createNestedArray_impl<const TString&>(key);
-  if (!array) return JsonArray::invalid();
+}
-  set(key, array);
+
-  return *array;
+template <typename TString>
+inline JsonArray JsonObject::createNestedArray(TString* key) {
+  return createNestedArray_impl<TString*>(key);
 }
 
 template <typename TStringRef>
-inline JsonObject &JsonObject::createNestedObject_impl(TStringRef key) {
+inline JsonArray JsonObject::createNestedArray_impl(TStringRef key) {
-  JsonObject *object = new (_buffer) JsonObject(_buffer);
+  if (!_data) return JsonArray();
-  if (!object) return JsonObject::invalid();
+  JsonArray array(_data->_buffer);
-  set(key, object);
+  if (!array.isNull()) set(key, array);
-  return *object;
+  return array;
+}
+
+template <typename TStringRef>
+inline JsonObject JsonObject::createNestedObject_impl(TStringRef key) {
+  if (!_data) return JsonObject();
+  JsonObject object(_data->_buffer);
+  if (!object.isNull()) set(key, object);
+  return object;
 }
 }  // namespace ArduinoJson

src/ArduinoJson/JsonObjectSubscript.hpp

@@ -22,7 +22,7 @@ class JsonObjectSubscript
   typedef JsonObjectSubscript<TStringRef> this_type;
 
  public:
-  FORCE_INLINE JsonObjectSubscript(JsonObject& object, TStringRef key)
+  FORCE_INLINE JsonObjectSubscript(JsonObject object, TStringRef key)
       : _object(object), _key(key) {}
 
   FORCE_INLINE this_type &operator=(const this_type &src) {
@@ -50,8 +50,8 @@ class JsonObjectSubscript
     return *this;
   }
 
-  FORCE_INLINE bool success() const {
+  FORCE_INLINE bool isNull() const {
-    return _object.containsKey(_key);
+    return !_object.containsKey(_key);
   }
 
   template <typename TValue>
@@ -88,9 +88,42 @@ class JsonObjectSubscript
   }
 
  private:
-  JsonObject& _object;
+  JsonObject _object;
   TStringRef _key;
 };
+
+template <typename TImpl>
+template <typename TString>
+inline typename enable_if<StringTraits<TString>::has_equals,
+                          const JsonObjectSubscript<const TString &> >::type
+    JsonVariantSubscripts<TImpl>::operator[](const TString &key) const {
+  return impl()->template as<JsonObject>()[key];
+}
+
+template <typename TImpl>
+template <typename TString>
+inline typename enable_if<StringTraits<TString>::has_equals,
+                          JsonObjectSubscript<const TString &> >::type
+    JsonVariantSubscripts<TImpl>::operator[](const TString &key) {
+  return impl()->template as<JsonObject>()[key];
+}
+
+template <typename TImpl>
+template <typename TString>
+inline typename enable_if<StringTraits<const TString *>::has_equals,
+                          JsonObjectSubscript<const TString *> >::type
+    JsonVariantSubscripts<TImpl>::operator[](const TString *key) {
+  return impl()->template as<JsonObject>()[key];
+}
+
+template <typename TImpl>
+template <typename TString>
+inline typename enable_if<StringTraits<TString *>::has_equals,
+                          const JsonObjectSubscript<const TString *> >::type
+    JsonVariantSubscripts<TImpl>::operator[](const TString *key) const {
+  return impl()->template as<JsonObject>()[key];
+}
+
 }  // namespace Internals
 }  // namespace ArduinoJson
 

src/ArduinoJson/JsonPair.hpp

@@ -8,9 +8,9 @@
 
 namespace ArduinoJson {
 
-// A key value pair for JsonObject.
+// A key value pair for JsonObjectData.
 struct JsonPair {
   const char* key;
   JsonVariant value;
 };
-}
+}  // namespace ArduinoJson

src/ArduinoJson/JsonVariant.hpp

@@ -104,25 +104,8 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
     _content.asString = value;
   }
 
-  // Create a JsonVariant containing a reference to an array.
+  JsonVariant(JsonArray array);
-  // CAUTION: we are lying about constness, because the array can be modified if
+  JsonVariant(JsonObject object);
-  // the variant is converted back to a JsonArray&
-  JsonVariant(const JsonArray &array);
-
-  // Create a JsonVariant containing a reference to an object.
-  // CAUTION: we are lying about constness, because the object can be modified
-  // if the variant is converted back to a JsonObject&
-  JsonVariant(const JsonObject &object);
-
-  JsonVariant(JsonArray *array) {
-    _content.asArray = array;
-    _type = Internals::JSON_ARRAY;
-  }
-
-  JsonVariant(JsonObject *object) {
-    _content.asObject = object;
-    _type = Internals::JSON_OBJECT;
-  }
 
   // Get the variant as the specified type.
   //
@@ -179,48 +162,23 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
     return s;
   }
   //
-  // JsonArray& as<JsonArray> const;
+  // JsonArray as<JsonArray>() const;
-  // JsonArray& as<JsonArray&> const;
+  // const JsonArray as<const JsonArray>() const;
   template <typename T>
   typename Internals::enable_if<
-      Internals::is_same<typename Internals::remove_reference<T>::type,
+      Internals::is_same<typename Internals::remove_const<T>::type,
                          JsonArray>::value,
-      JsonArray &>::type
+      JsonArray>::type
-  as() const {
+  as() const;
-    return variantAsArray();
-  }
   //
-  // const JsonArray& as<const JsonArray&> const;
+  // JsonObject as<JsonObject>() const;
+  // const JsonObject as<const JsonObject>() const;
   template <typename T>
   typename Internals::enable_if<
-      Internals::is_same<typename Internals::remove_reference<T>::type,
+      Internals::is_same<typename Internals::remove_const<T>::type,
-                         const JsonArray>::value,
-      const JsonArray &>::type
-  as() const {
-    return variantAsArray();
-  }
-  //
-  // JsonObject& as<JsonObject> const;
-  // JsonObject& as<JsonObject&> const;
-  template <typename T>
-  typename Internals::enable_if<
-      Internals::is_same<typename Internals::remove_reference<T>::type,
                          JsonObject>::value,
-      JsonObject &>::type
+      T>::type
-  as() const {
+  as() const;
-    return variantAsObject();
-  }
-  //
-  // JsonObject& as<const JsonObject> const;
-  // JsonObject& as<const JsonObject&> const;
-  template <typename T>
-  typename Internals::enable_if<
-      Internals::is_same<typename Internals::remove_reference<T>::type,
-                         const JsonObject>::value,
-      const JsonObject &>::type
-  as() const {
-    return variantAsObject();
-  }
   //
   // JsonVariant as<JsonVariant> const;
   template <typename T>
@@ -275,13 +233,10 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   }
   //
   // bool is<JsonArray> const;
-  // bool is<JsonArray&> const;
+  // bool is<const JsonArray> const;
-  // bool is<const JsonArray&> const;
   template <typename T>
   typename Internals::enable_if<
-      Internals::is_same<
+      Internals::is_same<typename Internals::remove_const<T>::type,
-          typename Internals::remove_const<
-              typename Internals::remove_reference<T>::type>::type,
                          JsonArray>::value,
       bool>::type
   is() const {
@@ -289,13 +244,10 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   }
   //
   // bool is<JsonObject> const;
-  // bool is<JsonObject&> const;
+  // bool is<const JsonObject> const;
-  // bool is<const JsonObject&> const;
   template <typename T>
   typename Internals::enable_if<
-      Internals::is_same<
+      Internals::is_same<typename Internals::remove_const<T>::type,
-          typename Internals::remove_const<
-              typename Internals::remove_reference<T>::type>::type,
                          JsonObject>::value,
       bool>::type
   is() const {
@@ -303,8 +255,8 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   }
 
   // Returns true if the variant has a value
-  bool success() const {
+  bool isNull() const {
-    return _type != Internals::JSON_UNDEFINED;
+    return _type == Internals::JSON_UNDEFINED;
   }
 
   template <typename Visitor>
@@ -315,10 +267,10 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
         return visitor.acceptFloat(_content.asFloat);
 
       case JSON_ARRAY:
-        return visitor.acceptArray(*_content.asArray);
+        return visitor.acceptArray(_content.asArray);
 
       case JSON_OBJECT:
-        return visitor.acceptObject(*_content.asObject);
+        return visitor.acceptObject(_content.asObject);
 
       case JSON_STRING:
         return visitor.acceptString(_content.asString);
@@ -336,13 +288,13 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
         return visitor.acceptBoolean(_content.asInteger != 0);
 
       default:  // JSON_UNDEFINED
-        return visitor.acceptUndefined();
+        return visitor.acceptNull();
     }
   }
 
  private:
-  JsonArray &variantAsArray() const;
+  JsonArray variantAsArray() const;
-  JsonObject &variantAsObject() const;
+  JsonObject variantAsObject() const;
   const char *variantAsString() const;
   template <typename T>
   T variantAsFloat() const;

src/ArduinoJson/JsonVariantCasts.hpp

@@ -13,21 +13,6 @@ namespace Internals {
 template <typename TImpl>
 class JsonVariantCasts {
  public:
-  // Gets the variant as an array.
-  // Returns a reference to the JsonArray or JsonArray::invalid() if the
-  // variant
-  // is not an array.
-  FORCE_INLINE operator JsonArray &() const {
-    return impl()->template as<JsonArray &>();
-  }
-
-  // Gets the variant as an object.
-  // Returns a reference to the JsonObject or JsonObject::invalid() if the
-  // variant is not an object.
-  FORCE_INLINE operator JsonObject &() const {
-    return impl()->template as<JsonObject &>();
-  }
-
   template <typename T>
   FORCE_INLINE operator T() const {
     return impl()->template as<T>();

src/ArduinoJson/JsonVariantComparisons.hpp

@@ -9,6 +9,9 @@
 #include "Strings/StringTraits.hpp"
 
 namespace ArduinoJson {
+class JsonArray;
+class JsonObject;
+
 namespace Internals {
 
 template <typename TImpl>

src/ArduinoJson/JsonVariantImpl.hpp

@@ -5,8 +5,8 @@
 #pragma once
 
 #include "Configuration.hpp"
-#include "JsonArray.hpp"
+#include "JsonArrayData.hpp"
-#include "JsonObject.hpp"
+#include "JsonObjectData.hpp"
 #include "JsonVariant.hpp"
 #include "Numbers/isFloat.hpp"
 #include "Numbers/isInteger.hpp"
@@ -17,32 +17,50 @@
 
 namespace ArduinoJson {
 
-inline JsonVariant::JsonVariant(const JsonArray &array) {
+inline JsonVariant::JsonVariant(JsonArray array) {
-  if (array.success()) {
+  if (!array.isNull()) {
     _type = Internals::JSON_ARRAY;
-    _content.asArray = const_cast<JsonArray *>(&array);
+    _content.asArray = array._data;
   } else {
     _type = Internals::JSON_UNDEFINED;
   }
 }
 
-inline JsonVariant::JsonVariant(const JsonObject &object) {
+inline JsonVariant::JsonVariant(JsonObject object) {
-  if (object.success()) {
+  if (!object.isNull()) {
     _type = Internals::JSON_OBJECT;
-    _content.asObject = const_cast<JsonObject *>(&object);
+    _content.asObject = object._data;
   } else {
     _type = Internals::JSON_UNDEFINED;
   }
 }
 
-inline JsonArray &JsonVariant::variantAsArray() const {
+template <typename T>
-  if (_type == Internals::JSON_ARRAY) return *_content.asArray;
+inline typename Internals::enable_if<
-  return JsonArray::invalid();
+    Internals::is_same<typename Internals::remove_const<T>::type,
+                       JsonArray>::value,
+    JsonArray>::type
+JsonVariant::as() const {
+  return variantAsArray();
 }
 
-inline JsonObject &JsonVariant::variantAsObject() const {
+template <typename T>
-  if (_type == Internals::JSON_OBJECT) return *_content.asObject;
+inline typename Internals::enable_if<
-  return JsonObject::invalid();
+    Internals::is_same<typename Internals::remove_const<T>::type,
+                       JsonObject>::value,
+    T>::type
+JsonVariant::as() const {
+  return variantAsObject();
+}
+
+inline JsonArray JsonVariant::variantAsArray() const {
+  if (_type == Internals::JSON_ARRAY) return _content.asArray;
+  return JsonArray();
+}
+
+inline JsonObject JsonVariant::variantAsObject() const {
+  if (_type == Internals::JSON_OBJECT) return _content.asObject;
+  return JsonObject();
 }
 
 template <typename T>

src/ArduinoJson/JsonVariantSubscripts.hpp

@@ -10,6 +10,8 @@
 #include "Strings/StringTraits.hpp"
 
 namespace ArduinoJson {
+class JsonArray;
+class JsonObject;
 namespace Internals {
 
 // Forward declarations.
@@ -30,14 +32,12 @@ class JsonVariantSubscripts {
 
   // Mimics an array.
   // Returns the element at specified index if the variant is an array.
-  // Returns JsonVariant::invalid() if the variant is not an array.
   FORCE_INLINE const JsonArraySubscript operator[](size_t index) const;
   FORCE_INLINE JsonArraySubscript operator[](size_t index);
 
   // Mimics an object.
   // Returns the value associated with the specified key if the variant is
   // an object.
-  // Return JsonVariant::invalid() if the variant is not an object.
   //
   // const JsonObjectSubscript operator[](TKey) const;
   // TKey = const std::string&, const String&
@@ -45,27 +45,21 @@ class JsonVariantSubscripts {
   FORCE_INLINE
       typename enable_if<StringTraits<TString>::has_equals,
                          const JsonObjectSubscript<const TString &> >::type
-      operator[](const TString &key) const {
+      operator[](const TString &key) const;
-    return impl()->template as<JsonObject>()[key];
-  }
   //
   // const JsonObjectSubscript operator[](TKey) const;
   // TKey = const std::string&, const String&
   template <typename TString>
   FORCE_INLINE typename enable_if<StringTraits<TString>::has_equals,
                                   JsonObjectSubscript<const TString &> >::type
-  operator[](const TString &key) {
+  operator[](const TString &key);
-    return impl()->template as<JsonObject>()[key];
-  }
   //
   // JsonObjectSubscript operator[](TKey);
   // TKey = const char*, const char[N], const FlashStringHelper*
   template <typename TString>
   FORCE_INLINE typename enable_if<StringTraits<const TString *>::has_equals,
                                   JsonObjectSubscript<const TString *> >::type
-  operator[](const TString *key) {
+  operator[](const TString *key);
-    return impl()->template as<JsonObject>()[key];
-  }
   //
   // JsonObjectSubscript operator[](TKey);
   // TKey = const char*, const char[N], const FlashStringHelper*
@@ -73,9 +67,7 @@ class JsonVariantSubscripts {
   FORCE_INLINE
       typename enable_if<StringTraits<TString *>::has_equals,
                          const JsonObjectSubscript<const TString *> >::type
-      operator[](const TString *key) const {
+      operator[](const TString *key) const;
-    return impl()->template as<JsonObject>()[key];
-  }
 
  private:
   const TImpl *impl() const {

src/ArduinoJson/Memory/JsonBuffer.hpp

@@ -9,7 +9,6 @@
 #include <string.h>
 
 #include "../Configuration.hpp"
-#include "../Polyfills/NonCopyable.hpp"
 #include "../Polyfills/attributes.hpp"
 
 namespace ArduinoJson {
@@ -17,7 +16,7 @@ namespace Internals {
 // Handle the memory management (done in derived classes) and calls the parser.
 // This abstract class is implemented by StaticJsonBuffer which implements a
 // fixed memory allocation.
-class JsonBuffer : NonCopyable {
+class JsonBuffer {
  public:
   // Allocates n bytes in the JsonBuffer.
   // Return a pointer to the allocated memory or NULL if allocation fails.

src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp

@@ -240,13 +240,13 @@ class MsgPackDeserializer {
   }
 
   DeserializationError readArray(JsonVariant &variant, size_t n) {
-    JsonArray *array = new (_buffer) JsonArray(_buffer);
+    JsonArray array(_buffer);
-    if (!array) return DeserializationError::NoMemory;
+    if (array.isNull()) return DeserializationError::NoMemory;
     variant = array;
-    return readArray(*array, n);
+    return readArray(array, n);
   }
 
-  DeserializationError readArray(JsonArray &array, size_t n) {
+  DeserializationError readArray(JsonArray array, size_t n) {
     if (_nestingLimit == 0) return DeserializationError::TooDeep;
     --_nestingLimit;
     for (; n; --n) {
@@ -267,13 +267,13 @@ class MsgPackDeserializer {
   }
 
   DeserializationError readObject(JsonVariant &variant, size_t n) {
-    JsonObject *object = new (_buffer) JsonObject(_buffer);
+    JsonObject object(_buffer);
-    if (!object) return DeserializationError::NoMemory;
+    if (object.isNull()) return DeserializationError::NoMemory;
     variant = object;
-    return readObject(*object, n);
+    return readObject(object, n);
   }
 
-  DeserializationError readObject(JsonObject &object, size_t n) {
+  DeserializationError readObject(JsonObject object, size_t n) {
     if (_nestingLimit == 0) return DeserializationError::TooDeep;
     --_nestingLimit;
     for (; n; --n) {

src/ArduinoJson/MsgPack/MsgPackSerializer.hpp

@@ -140,7 +140,7 @@ class MsgPackSerializer {
     writeByte(value ? 0xC3 : 0xC2);
   }
 
-  void acceptUndefined() {
+  void acceptNull() {
     writeByte(0xC0);
   }
 

src/ArduinoJson/Polyfills/NonCopyable.hpp

@@ -1,23 +0,0 @@
-// ArduinoJson - arduinojson.org
-// Copyright Benoit Blanchon 2014-2018
-// MIT License
-
-#pragma once
-
-namespace ArduinoJson {
-namespace Internals {
-
-// A type that cannot be copied
-class NonCopyable {
- protected:
-  NonCopyable() {}
-
- private:
-  // copy constructor is private
-  NonCopyable(const NonCopyable&);
-
-  // copy operator is private
-  NonCopyable& operator=(const NonCopyable&);
-};
-}
-}

src/ArduinoJson/StaticJsonDocument.hpp

@@ -33,28 +33,26 @@ class StaticJsonDocument {
     return _root.as<T>();
   }
 
-  // JsonObject& to<JsonObject>()
+  // JsonObject to<JsonObject>()
   template <typename T>
   typename Internals::enable_if<Internals::is_same<T, JsonObject>::value,
-                                JsonObject&>::type
+                                JsonObject>::type
   to() {
     clear();
-    JsonObject* object = new (&_buffer) JsonObject(&_buffer);
+    JsonObject object(&_buffer);
-    if (!object) return JsonObject::invalid();
     _root = object;
-    return *object;
+    return object;
   }
 
-  // JsonArray& to<JsonArray>()
+  // JsonArray to<JsonArray>()
   template <typename T>
   typename Internals::enable_if<Internals::is_same<T, JsonArray>::value,
-                                JsonArray&>::type
+                                JsonArray>::type
   to() {
     clear();
-    JsonArray* array = new (&_buffer) JsonArray(&_buffer);
+    JsonArray array(&_buffer);
-    if (!array) return JsonArray::invalid();
     _root = array;
-    return *array;
+    return array;
   }
 
   // JsonVariant to<JsonVariant>()

test/IntegrationTests/gbathree.cpp

@@ -20,7 +20,7 @@ TEST_CASE("Gbathree") {
       "\"measlights\":[[15,15,15,15],[15,15,15,15],[15,15,15,15],[15,15,"
       "15,15]],\"measlights2\":[[15,15,15,15],[15,15,15,15],[15,15,15,15],"
       "[15,15,15,15]],\"altc\":[2,2,2,2],\"altd\":[2,2,2,2]}");
-  JsonObject& root = doc.as<JsonObject>();
+  JsonObject root = doc.as<JsonObject>();
 
   SECTION("Success") {
     REQUIRE(error == DeserializationError::Ok);
@@ -81,8 +81,8 @@ TEST_CASE("Gbathree") {
   SECTION("Pulses") {
     // "pulses":[50,50,50]
 
-    JsonArray& array = root["pulses"];
+    JsonArray array = root["pulses"];
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
 
     REQUIRE(3 == array.size());
 
@@ -94,8 +94,8 @@ TEST_CASE("Gbathree") {
   SECTION("Act") {
     // "act":[2,1,2,2]
 
-    JsonArray& array = root["act"];
+    JsonArray array = root["act"];
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
 
     REQUIRE(4 == array.size());
     REQUIRE(2 == array[0]);
@@ -107,12 +107,12 @@ TEST_CASE("Gbathree") {
   SECTION("Detectors") {
     // "detectors":[[34,34,34,34],[34,34,34,34],[34,34,34,34],[34,34,34,34]]
 
-    JsonArray& array = root["detectors"];
+    JsonArray array = root["detectors"];
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
     REQUIRE(4 == array.size());
 
     for (size_t i = 0; i < 4; i++) {
-      JsonArray& nestedArray = array[i];
+      JsonArray nestedArray = array[i];
       REQUIRE(4 == nestedArray.size());
 
       for (size_t j = 0; j < 4; j++) {
@@ -124,8 +124,8 @@ TEST_CASE("Gbathree") {
   SECTION("Alta") {
     // alta:[2,2,2,2]
 
-    JsonArray& array = root["alta"];
+    JsonArray array = root["alta"];
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
 
     REQUIRE(4 == array.size());
 
@@ -137,8 +137,8 @@ TEST_CASE("Gbathree") {
   SECTION("Altb") {
     // altb:[2,2,2,2]
 
-    JsonArray& array = root["altb"];
+    JsonArray array = root["altb"];
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
 
     REQUIRE(4 == array.size());
 
@@ -150,12 +150,12 @@ TEST_CASE("Gbathree") {
   SECTION("Measlights") {
     // "measlights":[[15,15,15,15],[15,15,15,15],[15,15,15,15],[15,15,15,15]]
 
-    JsonArray& array = root["measlights"];
+    JsonArray array = root["measlights"];
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
     REQUIRE(4 == array.size());
 
     for (size_t i = 0; i < 4; i++) {
-      JsonArray& nestedArray = array[i];
+      JsonArray nestedArray = array[i];
 
       REQUIRE(4 == nestedArray.size());
 
@@ -168,12 +168,12 @@ TEST_CASE("Gbathree") {
   SECTION("Measlights2") {
     // "measlights2":[[15,15,15,15],[15,15,15,15],[15,15,15,15],[15,15,15,15]]
 
-    JsonArray& array = root["measlights2"];
+    JsonArray array = root["measlights2"];
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
     REQUIRE(4 == array.size());
 
     for (size_t i = 0; i < 4; i++) {
-      JsonArray& nestedArray = array[i];
+      JsonArray nestedArray = array[i];
       REQUIRE(4 == nestedArray.size());
 
       for (size_t j = 0; j < 4; j++) {
@@ -185,8 +185,8 @@ TEST_CASE("Gbathree") {
   SECTION("Altc") {
     // altc:[2,2,2,2]
 
-    JsonArray& array = root["altc"];
+    JsonArray array = root["altc"];
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
 
     REQUIRE(4 == array.size());
 
@@ -198,8 +198,8 @@ TEST_CASE("Gbathree") {
   SECTION("Altd") {
     // altd:[2,2,2,2]
 
-    JsonArray& array = root["altd"];
+    JsonArray array = root["altd"];
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
 
     REQUIRE(4 == array.size());
 

test/JsonArray/add.cpp

@@ -7,7 +7,7 @@
 
 TEST_CASE("JsonArray::add()") {
   DynamicJsonDocument doc;
-  JsonArray& _array = doc.to<JsonArray>();
+  JsonArray _array = doc.to<JsonArray>();
 
   SECTION("int") {
     _array.add(123);
@@ -40,30 +40,30 @@ TEST_CASE("JsonArray::add()") {
 
   SECTION("nested array") {
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
 
     _array.add(arr);
 
-    REQUIRE(&arr == &_array[0].as<JsonArray&>());
+    REQUIRE(arr == _array[0].as<JsonArray>());
-    REQUIRE(_array[0].is<JsonArray&>());
+    REQUIRE(_array[0].is<JsonArray>());
     REQUIRE_FALSE(_array[0].is<int>());
   }
 
   SECTION("nested object") {
     DynamicJsonDocument doc2;
-    JsonObject& obj = doc2.to<JsonObject>();
+    JsonObject obj = doc2.to<JsonObject>();
 
     _array.add(obj);
 
-    REQUIRE(&obj == &_array[0].as<JsonObject&>());
+    REQUIRE(obj == _array[0].as<JsonObject>());
-    REQUIRE(_array[0].is<JsonObject&>());
+    REQUIRE(_array[0].is<JsonObject>());
     REQUIRE_FALSE(_array[0].is<int>());
   }
 
   SECTION("array subscript") {
     const char* str = "hello";
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
     arr.add(str);
 
     _array.add(arr[0]);
@@ -74,7 +74,7 @@ TEST_CASE("JsonArray::add()") {
   SECTION("object subscript") {
     const char* str = "hello";
     DynamicJsonDocument doc2;
-    JsonObject& obj = doc2.to<JsonObject>();
+    JsonObject obj = doc2.to<JsonObject>();
     obj["x"] = str;
 
     _array.add(obj["x"]);

test/JsonArray/basics.cpp

@@ -7,10 +7,10 @@
 
 TEST_CASE("JsonArray basics") {
   DynamicJsonDocument doc;
-  JsonArray& array = doc.to<JsonArray>();
+  JsonArray array = doc.to<JsonArray>();
 
-  SECTION("SuccessIsTrue") {
+  SECTION("isNull()") {
-    REQUIRE(array.success());
+    REQUIRE(array.isNull() == false);
   }
 
   SECTION("InitialSizeIsZero") {
@@ -18,12 +18,12 @@ TEST_CASE("JsonArray basics") {
   }
 
   SECTION("CreateNestedArray") {
-    JsonArray& arr = array.createNestedArray();
+    JsonArray arr = array.createNestedArray();
-    REQUIRE(&arr == &array[0].as<JsonArray&>());
+    REQUIRE(arr == array[0].as<JsonArray>());
   }
 
   SECTION("CreateNestedObject") {
-    JsonObject& obj = array.createNestedObject();
+    JsonObject obj = array.createNestedObject();
-    REQUIRE(&obj == &array[0].as<JsonObject&>());
+    REQUIRE(obj == array[0].as<JsonObject>());
   }
 }

test/JsonArray/copyFrom.cpp

@@ -8,7 +8,7 @@
 TEST_CASE("JsonArray::copyFrom()") {
   SECTION("OneDimension") {
     DynamicJsonDocument doc;
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
     char json[32];
     int source[] = {1, 2, 3};
 
@@ -22,7 +22,7 @@ TEST_CASE("JsonArray::copyFrom()") {
   SECTION("OneDimension_JsonBufferTooSmall") {
     const size_t SIZE = JSON_ARRAY_SIZE(2);
     StaticJsonDocument<SIZE> doc;
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
     char json[32];
     int source[] = {1, 2, 3};
 
@@ -35,7 +35,7 @@ TEST_CASE("JsonArray::copyFrom()") {
 
   SECTION("TwoDimensions") {
     DynamicJsonDocument doc;
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
     char json[32];
     int source[][3] = {{1, 2, 3}, {4, 5, 6}};
 
@@ -50,7 +50,7 @@ TEST_CASE("JsonArray::copyFrom()") {
     const size_t SIZE =
         JSON_ARRAY_SIZE(2) + JSON_ARRAY_SIZE(3) + JSON_ARRAY_SIZE(2);
     StaticJsonDocument<SIZE> doc;
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
     char json[32];
     int source[][3] = {{1, 2, 3}, {4, 5, 6}};
 

test/JsonArray/copyTo.cpp

@@ -12,7 +12,7 @@ TEST_CASE("JsonArray::copyTo()") {
     char json[] = "[1,2,3]";
     DeserializationError err = deserializeJson(doc, json);
     REQUIRE(err == DeserializationError::Ok);
-    JsonArray& array = doc.as<JsonArray>();
+    JsonArray array = doc.as<JsonArray>();
 
     int destination[4] = {0};
     size_t result = array.copyTo(destination);
@@ -28,7 +28,7 @@ TEST_CASE("JsonArray::copyTo()") {
     char json[] = "[1,2,3]";
     DeserializationError err = deserializeJson(doc, json);
     REQUIRE(err == DeserializationError::Ok);
-    JsonArray& array = doc.as<JsonArray>();
+    JsonArray array = doc.as<JsonArray>();
 
     int destination[2] = {0};
     size_t result = array.copyTo(destination);
@@ -43,7 +43,7 @@ TEST_CASE("JsonArray::copyTo()") {
 
     DeserializationError err = deserializeJson(doc, json);
     REQUIRE(err == DeserializationError::Ok);
-    JsonArray& array = doc.as<JsonArray>();
+    JsonArray array = doc.as<JsonArray>();
 
     int destination[3][2] = {{0}};
     array.copyTo(destination);

test/JsonArray/invalid.cpp

@@ -7,28 +7,29 @@
 
 using namespace Catch::Matchers;
 
-TEST_CASE("JsonArray::invalid()") {
+TEST_CASE("Undefined JsonArray") {
+  JsonArray array;
+
   SECTION("SubscriptFails") {
-    REQUIRE_FALSE(JsonArray::invalid()[0].success());
+    REQUIRE(array[0].isNull());
   }
 
   SECTION("AddFails") {
-    JsonArray& array = JsonArray::invalid();
     array.add(1);
     REQUIRE(0 == array.size());
   }
 
   SECTION("CreateNestedArrayFails") {
-    REQUIRE_FALSE(JsonArray::invalid().createNestedArray().success());
+    REQUIRE(array.createNestedArray().isNull());
   }
 
   SECTION("CreateNestedObjectFails") {
-    REQUIRE_FALSE(JsonArray::invalid().createNestedObject().success());
+    REQUIRE(array.createNestedObject().isNull());
   }
 
   SECTION("PrintToWritesBrackets") {
     char buffer[32];
-    serializeJson(JsonArray::invalid(), buffer, sizeof(buffer));
+    serializeJson(array, buffer, sizeof(buffer));
-    REQUIRE_THAT(buffer, Equals("[]"));
+    REQUIRE_THAT(buffer, Equals("null"));
   }
 }

test/JsonArray/iterator.cpp

@@ -8,7 +8,7 @@
 template <typename TIterator>
 static void run_iterator_test() {
   StaticJsonDocument<JSON_ARRAY_SIZE(2)> doc;
-  JsonArray& array = doc.to<JsonArray>();
+  JsonArray array = doc.to<JsonArray>();
   array.add(12);
   array.add(34);
 

test/JsonArray/remove.cpp

@@ -7,7 +7,7 @@
 
 TEST_CASE("JsonArray::remove()") {
   DynamicJsonDocument doc;
-  JsonArray& _array = doc.to<JsonArray>();
+  JsonArray _array = doc.to<JsonArray>();
   _array.add(1);
   _array.add(2);
   _array.add(3);

test/JsonArray/set.cpp

@@ -9,7 +9,7 @@ using namespace Catch::Matchers;
 
 TEST_CASE("JsonArray::set()") {
   DynamicJsonDocument doc;
-  JsonArray& _array = doc.to<JsonArray>();
+  JsonArray _array = doc.to<JsonArray>();
   _array.add(0);
 
   SECTION("int") {
@@ -42,29 +42,29 @@ TEST_CASE("JsonArray::set()") {
 
   SECTION("nested array") {
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
 
     _array.set(0, arr);
 
-    REQUIRE(&arr == &_array[0].as<JsonArray&>());
+    REQUIRE(arr == _array[0].as<JsonArray>());
-    REQUIRE(_array[0].is<JsonArray&>());
+    REQUIRE(_array[0].is<JsonArray>());
     REQUIRE_FALSE(_array[0].is<int>());
   }
 
   SECTION("nested object") {
     DynamicJsonDocument doc2;
-    JsonObject& obj = doc2.to<JsonObject>();
+    JsonObject obj = doc2.to<JsonObject>();
 
     _array.set(0, obj);
 
-    REQUIRE(&obj == &_array[0].as<JsonObject&>());
+    REQUIRE(obj == _array[0].as<JsonObject>());
-    REQUIRE(_array[0].is<JsonObject&>());
+    REQUIRE(_array[0].is<JsonObject>());
     REQUIRE_FALSE(_array[0].is<int>());
   }
 
   SECTION("array subscript") {
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
     arr.add("hello");
 
     _array.set(0, arr[0]);
@@ -74,7 +74,7 @@ TEST_CASE("JsonArray::set()") {
 
   SECTION("object subscript") {
     DynamicJsonDocument doc2;
-    JsonObject& obj = doc2.to<JsonObject>();
+    JsonObject obj = doc2.to<JsonObject>();
     obj["x"] = "hello";
 
     _array.set(0, obj["x"]);

test/JsonArray/size.cpp

@@ -7,7 +7,7 @@
 
 TEST_CASE("JsonArray::size()") {
   DynamicJsonDocument doc;
-  JsonArray& _array = doc.to<JsonArray>();
+  JsonArray _array = doc.to<JsonArray>();
 
   SECTION("increases after add()") {
     _array.add("hello");

test/JsonArray/std_string.cpp

@@ -12,7 +12,7 @@ static void eraseString(std::string &str) {
 
 TEST_CASE("std::string") {
   DynamicJsonDocument doc;
-  JsonArray &array = doc.to<JsonArray>();
+  JsonArray array = doc.to<JsonArray>();
 
   SECTION("add()") {
     std::string value("hello");

test/JsonArray/subscript.cpp

@@ -8,7 +8,7 @@
 
 TEST_CASE("JsonArray::operator[]") {
   DynamicJsonDocument doc;
-  JsonArray& _array = doc.to<JsonArray>();
+  JsonArray _array = doc.to<JsonArray>();
   _array.add(0);
 
   SECTION("int") {
@@ -53,35 +53,33 @@ TEST_CASE("JsonArray::operator[]") {
 
   SECTION("nested array") {
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
 
     _array[0] = arr;
 
-    REQUIRE(&arr == &_array[0].as<JsonArray&>());
+    REQUIRE(arr == _array[0].as<JsonArray>());
-    REQUIRE(&arr == &_array[0].as<JsonArray>());  // <- short hand
+    REQUIRE(arr == _array[0].as<JsonArray>());  // <- short hand
-    REQUIRE(&arr == &_array[0].as<const JsonArray&>());
+    // REQUIRE(arr == _array[0].as<const JsonArray>());
-    REQUIRE(&arr == &_array[0].as<const JsonArray>());  // <- short hand
+    // REQUIRE(arr == _array[0].as<const JsonArray>());  // <- short hand
-    REQUIRE(true == _array[0].is<JsonArray&>());
+    REQUIRE(true == _array[0].is<JsonArray>());
     REQUIRE(false == _array[0].is<int>());
   }
 
   SECTION("nested object") {
     DynamicJsonDocument doc2;
-    JsonObject& obj = doc2.to<JsonObject>();
+    JsonObject obj = doc2.to<JsonObject>();
 
     _array[0] = obj;
 
-    REQUIRE(&obj == &_array[0].as<JsonObject&>());
+    REQUIRE(obj == _array[0].as<JsonObject>());
-    REQUIRE(&obj == &_array[0].as<JsonObject>());  // <- short hand
+    REQUIRE(obj == _array[0].as<const JsonObject>());  // <- short hand
-    REQUIRE(&obj == &_array[0].as<const JsonObject&>());
+    REQUIRE(true == _array[0].is<JsonObject>());
-    REQUIRE(&obj == &_array[0].as<const JsonObject>());  // <- short hand
-    REQUIRE(true == _array[0].is<JsonObject&>());
     REQUIRE(false == _array[0].is<int>());
   }
 
   SECTION("array subscript") {
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
     const char* str = "hello";
 
     arr.add(str);
@@ -94,7 +92,7 @@ TEST_CASE("JsonArray::operator[]") {
   SECTION("object subscript") {
     const char* str = "hello";
     DynamicJsonDocument doc2;
-    JsonObject& obj = doc2.to<JsonObject>();
+    JsonObject obj = doc2.to<JsonObject>();
 
     obj["x"] = str;
 

test/JsonDeserializer/deserializeJsonArray.cpp

@@ -10,7 +10,7 @@ TEST_CASE("deserialize JSON array") {
 
   SECTION("An empty array") {
     DeserializationError err = deserializeJson(doc, "[]");
-    JsonArray& arr = doc.as<JsonArray>();
+    JsonArray arr = doc.as<JsonArray>();
 
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(0 == arr.size());
@@ -19,7 +19,7 @@ TEST_CASE("deserialize JSON array") {
   SECTION("Spaces") {
     SECTION("Before the opening bracket") {
       DeserializationError err = deserializeJson(doc, "  []");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(0 == arr.size());
@@ -27,7 +27,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Before first value") {
       DeserializationError err = deserializeJson(doc, "[ \t\r\n42]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -36,7 +36,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("After first value") {
       DeserializationError err = deserializeJson(doc, "[42 \t\r\n]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -47,7 +47,7 @@ TEST_CASE("deserialize JSON array") {
   SECTION("Values types") {
     SECTION("On integer") {
       DeserializationError err = deserializeJson(doc, "[42]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -56,7 +56,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Two integers") {
       DeserializationError err = deserializeJson(doc, "[42,84]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -66,7 +66,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Double") {
       DeserializationError err = deserializeJson(doc, "[4.2,1e2]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -76,7 +76,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Unsigned long") {
       DeserializationError err = deserializeJson(doc, "[4294967295]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -85,7 +85,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Boolean") {
       DeserializationError err = deserializeJson(doc, "[true,false]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -95,7 +95,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Null") {
       DeserializationError err = deserializeJson(doc, "[null,null]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -108,7 +108,7 @@ TEST_CASE("deserialize JSON array") {
     SECTION("Double quotes") {
       DeserializationError err =
           deserializeJson(doc, "[ \"hello\" , \"world\" ]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -118,7 +118,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Single quotes") {
       DeserializationError err = deserializeJson(doc, "[ 'hello' , 'world' ]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -128,7 +128,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("No quotes") {
       DeserializationError err = deserializeJson(doc, "[ hello , world ]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -138,7 +138,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Double quotes (empty strings)") {
       DeserializationError err = deserializeJson(doc, "[\"\",\"\"]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -148,7 +148,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Single quotes (empty strings)") {
       DeserializationError err = deserializeJson(doc, "[\'\',\'\']");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -179,7 +179,7 @@ TEST_CASE("deserialize JSON array") {
     SECTION("Before opening bracket") {
       DeserializationError err =
           deserializeJson(doc, "/*COMMENT*/  [\"hello\"]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -189,7 +189,7 @@ TEST_CASE("deserialize JSON array") {
     SECTION("After opening bracket") {
       DeserializationError err =
           deserializeJson(doc, "[/*COMMENT*/ \"hello\"]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -198,7 +198,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("Before closing bracket") {
       DeserializationError err = deserializeJson(doc, "[\"hello\"/*COMMENT*/]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -207,7 +207,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("After closing bracket") {
       DeserializationError err = deserializeJson(doc, "[\"hello\"]/*COMMENT*/");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -217,7 +217,7 @@ TEST_CASE("deserialize JSON array") {
     SECTION("Before comma") {
       DeserializationError err =
           deserializeJson(doc, "[\"hello\"/*COMMENT*/,\"world\"]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -228,7 +228,7 @@ TEST_CASE("deserialize JSON array") {
     SECTION("After comma") {
       DeserializationError err =
           deserializeJson(doc, "[\"hello\",/*COMMENT*/ \"world\"]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -256,7 +256,7 @@ TEST_CASE("deserialize JSON array") {
     SECTION("Before opening bracket") {
       DeserializationError err =
           deserializeJson(doc, "//COMMENT\n\t[\"hello\"]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -265,7 +265,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("After opening bracket") {
       DeserializationError err = deserializeJson(doc, "[//COMMENT\n\"hello\"]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -275,7 +275,7 @@ TEST_CASE("deserialize JSON array") {
     SECTION("Before closing bracket") {
       DeserializationError err =
           deserializeJson(doc, "[\"hello\"//COMMENT\r\n]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -284,7 +284,7 @@ TEST_CASE("deserialize JSON array") {
 
     SECTION("After closing bracket") {
       DeserializationError err = deserializeJson(doc, "[\"hello\"]//COMMENT\n");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(1 == arr.size());
@@ -294,7 +294,7 @@ TEST_CASE("deserialize JSON array") {
     SECTION("Before comma") {
       DeserializationError err =
           deserializeJson(doc, "[\"hello\"//COMMENT\n,\"world\"]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -305,7 +305,7 @@ TEST_CASE("deserialize JSON array") {
     SECTION("After comma") {
       DeserializationError err =
           deserializeJson(doc, "[\"hello\",//COMMENT\n\"world\"]");
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
@@ -372,17 +372,17 @@ TEST_CASE("deserialize JSON array") {
           " [ { \"a\" : 1 , \"b\" : 2 } , { \"c\" : 3 , \"d\" : 4 } ] ";
 
       DeserializationError err = deserializeJson(doc, jsonString);
-      JsonArray& arr = doc.as<JsonArray>();
+      JsonArray arr = doc.as<JsonArray>();
 
-      JsonObject& object1 = arr[0];
+      JsonObject object1 = arr[0];
-      const JsonObject& object2 = arr[1];
+      const JsonObject object2 = arr[1];
-      JsonObject& object3 = arr[2];
+      JsonObject object3 = arr[2];
 
       REQUIRE(err == DeserializationError::Ok);
 
-      REQUIRE(true == object1.success());
+      REQUIRE(object1.isNull() == false);
-      REQUIRE(true == object2.success());
+      REQUIRE(object2.isNull() == false);
-      REQUIRE(false == object3.success());
+      REQUIRE(object3.isNull() == true);
 
       REQUIRE(2 == object1.size());
       REQUIRE(2 == object2.size());
@@ -399,7 +399,7 @@ TEST_CASE("deserialize JSON array") {
   SECTION("Should clear the JsonArray") {
     deserializeJson(doc, "[1,2,3,4]");
     deserializeJson(doc, "[]");
-    JsonArray& arr = doc.as<JsonArray>();
+    JsonArray arr = doc.as<JsonArray>();
 
     REQUIRE(arr.size() == 0);
     REQUIRE(doc.memoryUsage() == JSON_ARRAY_SIZE(0));

test/JsonDeserializer/deserializeJsonArrayStatic.cpp

@@ -68,7 +68,7 @@ TEST_CASE("deserialize JSON array with a StaticJsonDocument") {
     deserializeJson(doc, input);
     deserializeJson(doc, "[]");
 
-    JsonArray& arr = doc.as<JsonArray>();
+    JsonArray arr = doc.as<JsonArray>();
     REQUIRE(arr.size() == 0);
     REQUIRE(doc.memoryUsage() == JSON_ARRAY_SIZE(0));
   }
@@ -78,7 +78,7 @@ TEST_CASE("deserialize JSON array with a StaticJsonDocument") {
     char input[] = "[1,2]";
 
     DeserializationError err = deserializeJson(doc, input);
-    JsonArray& arr = doc.as<JsonArray>();
+    JsonArray arr = doc.as<JsonArray>();
 
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(doc.is<JsonArray>());

test/JsonDeserializer/deserializeJsonObject.cpp

@@ -10,7 +10,7 @@ TEST_CASE("deserialize JSON object") {
 
   SECTION("An empty object") {
     DeserializationError err = deserializeJson(doc, "{}");
-    JsonObject& obj = doc.as<JsonObject>();
+    JsonObject obj = doc.as<JsonObject>();
 
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(doc.is<JsonObject>());
@@ -20,7 +20,7 @@ TEST_CASE("deserialize JSON object") {
   SECTION("Quotes") {
     SECTION("Double quotes") {
       DeserializationError err = deserializeJson(doc, "{\"key\":\"value\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -30,7 +30,7 @@ TEST_CASE("deserialize JSON object") {
 
     SECTION("Single quotes") {
       DeserializationError err = deserializeJson(doc, "{'key':'value'}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -40,7 +40,7 @@ TEST_CASE("deserialize JSON object") {
 
     SECTION("No quotes") {
       DeserializationError err = deserializeJson(doc, "{key:value}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -50,7 +50,7 @@ TEST_CASE("deserialize JSON object") {
 
     SECTION("No quotes, allow underscore in key") {
       DeserializationError err = deserializeJson(doc, "{_k_e_y_:42}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -62,7 +62,7 @@ TEST_CASE("deserialize JSON object") {
   SECTION("Spaces") {
     SECTION("Before the key") {
       DeserializationError err = deserializeJson(doc, "{ \"key\":\"value\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -72,7 +72,7 @@ TEST_CASE("deserialize JSON object") {
 
     SECTION("After the key") {
       DeserializationError err = deserializeJson(doc, "{\"key\" :\"value\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -82,7 +82,7 @@ TEST_CASE("deserialize JSON object") {
 
     SECTION("Before the value") {
       DeserializationError err = deserializeJson(doc, "{\"key\": \"value\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -92,7 +92,7 @@ TEST_CASE("deserialize JSON object") {
 
     SECTION("After the value") {
       DeserializationError err = deserializeJson(doc, "{\"key\":\"value\" }");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -103,7 +103,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Before the colon") {
       DeserializationError err =
           deserializeJson(doc, "{\"key1\":\"value1\" ,\"key2\":\"value2\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -115,7 +115,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("After the colon") {
       DeserializationError err =
           deserializeJson(doc, "{\"key1\":\"value1\" ,\"key2\":\"value2\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -129,7 +129,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("String") {
       DeserializationError err =
           deserializeJson(doc, "{\"key1\":\"value1\",\"key2\":\"value2\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -141,7 +141,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Integer") {
       DeserializationError err =
           deserializeJson(doc, "{\"key1\":42,\"key2\":-42}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -153,7 +153,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Double") {
       DeserializationError err =
           deserializeJson(doc, "{\"key1\":12.345,\"key2\":-7E89}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -165,7 +165,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Booleans") {
       DeserializationError err =
           deserializeJson(doc, "{\"key1\":true,\"key2\":false}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -177,7 +177,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Null") {
       DeserializationError err =
           deserializeJson(doc, "{\"key1\":null,\"key2\":null}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -190,17 +190,17 @@ TEST_CASE("deserialize JSON object") {
       char jsonString[] = " { \"ab\" : [ 1 , 2 ] , \"cd\" : [ 3 , 4 ] } ";
 
       DeserializationError err = deserializeJson(doc, jsonString);
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
-      JsonArray& array1 = obj["ab"];
+      JsonArray array1 = obj["ab"];
-      const JsonArray& array2 = obj["cd"];
+      const JsonArray array2 = obj["cd"];
-      JsonArray& array3 = obj["ef"];
+      JsonArray array3 = obj["ef"];
 
       REQUIRE(err == DeserializationError::Ok);
 
-      REQUIRE(true == array1.success());
+      REQUIRE(array1.isNull() == false);
-      REQUIRE(true == array2.success());
+      REQUIRE(array2.isNull() == false);
-      REQUIRE(false == array3.success());
+      REQUIRE(array3.isNull() == true);
 
       REQUIRE(2 == array1.size());
       REQUIRE(2 == array2.size());
@@ -278,7 +278,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Before opening brace") {
       DeserializationError err =
           deserializeJson(doc, "/*COMMENT*/ {\"hello\":\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -287,7 +287,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("After opening brace") {
       DeserializationError err =
           deserializeJson(doc, "{/*COMMENT*/\"hello\":\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -296,7 +296,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Before colon") {
       DeserializationError err =
           deserializeJson(doc, "{\"hello\"/*COMMENT*/:\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -305,7 +305,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("After colon") {
       DeserializationError err =
           deserializeJson(doc, "{\"hello\":/*COMMENT*/\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -314,7 +314,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Before closing brace") {
       DeserializationError err =
           deserializeJson(doc, "{\"hello\":\"world\"/*COMMENT*/}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -323,7 +323,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("After closing brace") {
       DeserializationError err =
           deserializeJson(doc, "{\"hello\":\"world\"}/*COMMENT*/");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -332,7 +332,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Before comma") {
       DeserializationError err = deserializeJson(
           doc, "{\"hello\":\"world\"/*COMMENT*/,\"answer\":42}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -342,7 +342,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("After comma") {
       DeserializationError err = deserializeJson(
           doc, "{\"hello\":\"world\",/*COMMENT*/\"answer\":42}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -354,7 +354,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Before opening brace") {
       DeserializationError err =
           deserializeJson(doc, "//COMMENT\n {\"hello\":\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -363,7 +363,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("After opening brace") {
       DeserializationError err =
           deserializeJson(doc, "{//COMMENT\n\"hello\":\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -372,7 +372,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Before colon") {
       DeserializationError err =
           deserializeJson(doc, "{\"hello\"//COMMENT\n:\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -381,7 +381,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("After colon") {
       DeserializationError err =
           deserializeJson(doc, "{\"hello\"://COMMENT\n\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -390,7 +390,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Before closing brace") {
       DeserializationError err =
           deserializeJson(doc, "{\"hello\":\"world\"//COMMENT\n}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -399,7 +399,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("After closing brace") {
       DeserializationError err =
           deserializeJson(doc, "{\"hello\":\"world\"}//COMMENT\n");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -408,7 +408,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("Before comma") {
       DeserializationError err = deserializeJson(
           doc, "{\"hello\":\"world\"//COMMENT\n,\"answer\":42}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -418,7 +418,7 @@ TEST_CASE("deserialize JSON object") {
     SECTION("After comma") {
       DeserializationError err = deserializeJson(
           doc, "{\"hello\":\"world\",//COMMENT\n\"answer\":42}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -459,7 +459,7 @@ TEST_CASE("deserialize JSON object") {
 
     SECTION("After closing brace") {
       DeserializationError err = deserializeJson(doc, "{\"hello\":\"world\"}/");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(obj["hello"] == "world");
@@ -483,7 +483,7 @@ TEST_CASE("deserialize JSON object") {
   SECTION("Should clear the JsonObject") {
     deserializeJson(doc, "{\"hello\":\"world\"}");
     deserializeJson(doc, "{}");
-    JsonObject& obj = doc.as<JsonObject>();
+    JsonObject obj = doc.as<JsonObject>();
 
     REQUIRE(doc.is<JsonObject>());
     REQUIRE(obj.size() == 0);

test/JsonDeserializer/std_istream.cpp

@@ -13,7 +13,7 @@ TEST_CASE("deserializeJson(std::istream&)") {
     std::istringstream json(" [ 42 /* comment */ ] ");
 
     DeserializationError err = deserializeJson(doc, json);
-    JsonArray& arr = doc.as<JsonArray>();
+    JsonArray arr = doc.as<JsonArray>();
 
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(1 == arr.size());
@@ -24,7 +24,7 @@ TEST_CASE("deserializeJson(std::istream&)") {
     std::istringstream json(" { hello : world // comment\n }");
 
     DeserializationError err = deserializeJson(doc, json);
-    JsonObject& obj = doc.as<JsonObject>();
+    JsonObject obj = doc.as<JsonObject>();
 
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(1 == obj.size());

test/JsonDeserializer/std_string.cpp

@@ -28,7 +28,7 @@ TEST_CASE("deserializeJson(const std::string&)") {
     DeserializationError err = deserializeJson(doc, input);
     input[2] = 'X';  // alter the string tomake sure we made a copy
 
-    JsonArray &array = doc.as<JsonArray>();
+    JsonArray array = doc.as<JsonArray>();
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(std::string("hello") == array[0]);
   }

test/JsonObject/basics.cpp

@@ -7,9 +7,9 @@
 
 TEST_CASE("JsonObject basics") {
   DynamicJsonDocument doc;
-  JsonObject& obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
 
-  SECTION("SuccessIsTrue") {
+  SECTION("isNull()") {
-    REQUIRE(obj.success());
+    REQUIRE(obj.isNull() == false);
   }
 }

test/JsonObject/containsKey.cpp

@@ -7,7 +7,7 @@
 
 TEST_CASE("JsonObject::containsKey()") {
   DynamicJsonDocument doc;
-  JsonObject& obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
 
   SECTION("ContainsKeyReturnsFalseForNonExistingKey") {
     obj.set("hello", 42);

test/JsonObject/get.cpp

@@ -9,7 +9,7 @@ using namespace Catch::Matchers;
 
 TEST_CASE("JsonObject::get()") {
   DynamicJsonDocument doc;
-  JsonObject& obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
 
   SECTION("GetConstCharPointer_GivenStringLiteral") {
     obj.set("hello", "world");

test/JsonObject/invalid.cpp

@@ -8,10 +8,10 @@
 using namespace Catch::Matchers;
 
 TEST_CASE("JsonObject::invalid()") {
-  JsonObject& obj = JsonObject::invalid();
+  JsonObject obj;
 
   SECTION("SubscriptFails") {
-    REQUIRE_FALSE(obj["key"].success());
+    REQUIRE(obj["key"].isNull());
   }
 
   SECTION("AddFails") {
@@ -20,16 +20,16 @@ TEST_CASE("JsonObject::invalid()") {
   }
 
   SECTION("CreateNestedArrayFails") {
-    REQUIRE_FALSE(obj.createNestedArray("hello").success());
+    REQUIRE(obj.createNestedArray("hello").isNull());
   }
 
   SECTION("CreateNestedObjectFails") {
-    REQUIRE_FALSE(obj.createNestedObject("world").success());
+    REQUIRE(obj.createNestedObject("world").isNull());
   }
 
-  SECTION("PrintToWritesBraces") {
+  SECTION("serialize to 'null'") {
     char buffer[32];
     serializeJson(obj, buffer, sizeof(buffer));
-    REQUIRE_THAT(buffer, Equals("{}"));
+    REQUIRE_THAT(buffer, Equals("null"));
   }
 }

test/JsonObject/iterator.cpp

@@ -9,7 +9,7 @@ using namespace Catch::Matchers;
 
 TEST_CASE("JsonObject::begin()/end()") {
   StaticJsonDocument<JSON_OBJECT_SIZE(2)> doc;
-  JsonObject& obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
   obj["ab"] = 12;
   obj["cd"] = 34;
 
@@ -35,7 +35,7 @@ TEST_CASE("JsonObject::begin()/end()") {
   }
 
   SECTION("ConstIterator") {
-    const JsonObject& const_object = obj;
+    const JsonObject const_object = obj;
     JsonObject::const_iterator it = const_object.begin();
 
     REQUIRE(const_object.end() != it);

test/JsonObject/remove.cpp

@@ -8,7 +8,7 @@
 
 TEST_CASE("JsonObject::remove()") {
   DynamicJsonDocument doc;
-  JsonObject& obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
 
   SECTION("SizeDecreased_WhenValuesAreRemoved") {
     obj["hello"] = 1;

test/JsonObject/set.cpp

@@ -8,7 +8,7 @@
 
 TEST_CASE("JsonObject::set()") {
   DynamicJsonDocument doc;
-  JsonObject& obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
 
   SECTION("int") {
     obj.set("hello", 123);
@@ -44,29 +44,29 @@ TEST_CASE("JsonObject::set()") {
 
   SECTION("nested array") {
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
 
     obj.set("hello", arr);
 
-    REQUIRE(&arr == &obj["hello"].as<JsonArray>());
+    REQUIRE(arr == obj["hello"].as<JsonArray>());
-    REQUIRE(obj["hello"].is<JsonArray&>());
+    REQUIRE(obj["hello"].is<JsonArray>());
-    REQUIRE_FALSE(obj["hello"].is<JsonObject&>());
+    REQUIRE_FALSE(obj["hello"].is<JsonObject>());
   }
 
   SECTION("nested object") {
     DynamicJsonDocument doc2;
-    JsonObject& obj2 = doc2.to<JsonObject>();
+    JsonObject obj2 = doc2.to<JsonObject>();
 
     obj.set("hello", obj2);
 
-    REQUIRE(&obj2 == &obj["hello"].as<JsonObject>());
+    REQUIRE(obj2 == obj["hello"].as<JsonObject>());
-    REQUIRE(obj["hello"].is<JsonObject&>());
+    REQUIRE(obj["hello"].is<JsonObject>());
-    REQUIRE_FALSE(obj["hello"].is<JsonArray&>());
+    REQUIRE_FALSE(obj["hello"].is<JsonArray>());
   }
 
   SECTION("array subscript") {
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
     arr.add(42);
 
     obj.set("a", arr[0]);
@@ -76,7 +76,7 @@ TEST_CASE("JsonObject::set()") {
 
   SECTION("object subscript") {
     DynamicJsonDocument doc2;
-    JsonObject& obj2 = doc2.to<JsonObject>();
+    JsonObject obj2 = doc2.to<JsonObject>();
     obj2.set("x", 42);
 
     obj.set("a", obj2["x"]);
@@ -86,14 +86,14 @@ TEST_CASE("JsonObject::set()") {
 
   SECTION("returns true when allocation succeeds") {
     StaticJsonDocument<JSON_OBJECT_SIZE(1) + 15> doc2;
-    JsonObject& obj2 = doc2.to<JsonObject>();
+    JsonObject obj2 = doc2.to<JsonObject>();
 
     REQUIRE(true == obj2.set(std::string("hello"), std::string("world")));
   }
 
   SECTION("returns false when allocation fails") {
     StaticJsonDocument<JSON_OBJECT_SIZE(1) + 10> doc2;
-    JsonObject& obj2 = doc2.to<JsonObject>();
+    JsonObject obj2 = doc2.to<JsonObject>();
 
     REQUIRE(false == obj2.set(std::string("hello"), std::string("world")));
   }

test/JsonObject/size.cpp

@@ -8,7 +8,7 @@
 
 TEST_CASE("JsonObject::size()") {
   DynamicJsonDocument doc;
-  JsonObject& obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
 
   SECTION("initial size is zero") {
     REQUIRE(0 == obj.size());

test/JsonObject/std_string.cpp

@@ -17,7 +17,7 @@ TEST_CASE("std::string") {
     char json[] = "{\"key\":\"value\"}";
 
     deserializeJson(doc, json);
-    JsonObject &obj = doc.as<JsonObject>();
+    JsonObject obj = doc.as<JsonObject>();
 
     REQUIRE(std::string("value") == obj[std::string("key")]);
   }
@@ -26,13 +26,13 @@ TEST_CASE("std::string") {
     char json[] = "{\"key\":\"value\"}";
 
     deserializeJson(doc, json);
-    JsonObject &obj = doc.as<JsonObject>();
+    JsonObject obj = doc.as<JsonObject>();
 
     REQUIRE(std::string("value") == obj[std::string("key")]);
   }
 
   SECTION("set(key)") {
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     std::string key("hello");
     obj.set(key, "world");
     eraseString(key);
@@ -40,7 +40,7 @@ TEST_CASE("std::string") {
   }
 
   SECTION("set(value)") {
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     std::string value("world");
     obj.set("hello", value);
     eraseString(value);
@@ -48,7 +48,7 @@ TEST_CASE("std::string") {
   }
 
   SECTION("set(key,value)") {
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     std::string key("hello");
     std::string value("world");
     obj.set(key, value);
@@ -58,9 +58,9 @@ TEST_CASE("std::string") {
   }
 
   SECTION("set(JsonArraySubscript)") {
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     DynamicJsonDocument doc2;
-    JsonArray &arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
     arr.add("world");
 
     obj.set(std::string("hello"), arr[0]);
@@ -69,9 +69,9 @@ TEST_CASE("std::string") {
   }
 
   SECTION("set(JsonObjectSubscript)") {
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     DynamicJsonDocument doc2;
-    JsonObject &obj2 = doc2.to<JsonObject>();
+    JsonObject obj2 = doc2.to<JsonObject>();
     obj2.set("x", "world");
 
     obj.set(std::string("hello"), obj2["x"]);
@@ -82,7 +82,7 @@ TEST_CASE("std::string") {
   SECTION("get<T>()") {
     char json[] = "{\"key\":\"value\"}";
     deserializeJson(doc, json);
-    JsonObject &obj = doc.as<JsonObject>();
+    JsonObject obj = doc.as<JsonObject>();
 
     REQUIRE(std::string("value") == obj.get<const char *>(std::string("key")));
   }
@@ -90,13 +90,13 @@ TEST_CASE("std::string") {
   SECTION("is<T>()") {
     char json[] = "{\"key\":\"value\"}";
     deserializeJson(doc, json);
-    JsonObject &obj = doc.as<JsonObject>();
+    JsonObject obj = doc.as<JsonObject>();
 
     REQUIRE(true == obj.is<const char *>(std::string("key")));
   }
 
   SECTION("createNestedObject()") {
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     std::string key = "key";
     char json[64];
     obj.createNestedObject(key);
@@ -106,7 +106,7 @@ TEST_CASE("std::string") {
   }
 
   SECTION("createNestedArray()") {
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     std::string key = "key";
     char json[64];
     obj.createNestedArray(key);
@@ -118,12 +118,12 @@ TEST_CASE("std::string") {
   SECTION("containsKey()") {
     char json[] = "{\"key\":\"value\"}";
     deserializeJson(doc, json);
-    JsonObject &obj = doc.as<JsonObject>();
+    JsonObject obj = doc.as<JsonObject>();
     REQUIRE(true == obj.containsKey(std::string("key")));
   }
 
   SECTION("remove()") {
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     obj["key"] = "value";
 
     obj.remove(std::string("key"));
@@ -133,7 +133,7 @@ TEST_CASE("std::string") {
 
   SECTION("operator[], set key") {
     std::string key("hello");
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     obj[key] = "world";
     eraseString(key);
     REQUIRE(std::string("world") == obj["hello"]);
@@ -141,7 +141,7 @@ TEST_CASE("std::string") {
 
   SECTION("operator[], set value") {
     std::string value("world");
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     obj["hello"] = value;
     eraseString(value);
     REQUIRE(std::string("world") == obj["hello"]);
@@ -149,7 +149,7 @@ TEST_CASE("std::string") {
 
   SECTION("memoryUsage() increases when adding a new key") {
     std::string key1("hello"), key2("world");
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
 
     obj[key1] = 1;
     size_t sizeBefore = doc.memoryUsage();
@@ -161,7 +161,7 @@ TEST_CASE("std::string") {
 
   SECTION("memoryUsage() remains when adding the same key") {
     std::string key("hello");
-    JsonObject &obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
 
     obj[key] = 1;
     size_t sizeBefore = doc.memoryUsage();

test/JsonObject/subscript.cpp

@@ -7,7 +7,7 @@
 
 TEST_CASE("JsonObject::operator[]") {
   DynamicJsonDocument doc;
-  JsonObject& obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
 
   SECTION("int") {
     obj["hello"] = 123;
@@ -53,41 +53,37 @@ TEST_CASE("JsonObject::operator[]") {
 
   SECTION("array") {
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
 
     obj["hello"] = arr;
 
-    REQUIRE(&arr == &obj["hello"].as<JsonArray&>());
+    REQUIRE(arr == obj["hello"].as<JsonArray>());
-    REQUIRE(&arr == &obj["hello"].as<JsonArray>());  // <- short hand
+    REQUIRE(arr == obj["hello"].as<JsonArray>());  // <- short hand
-    REQUIRE(&arr == &obj["hello"].as<const JsonArray&>());
+    // REQUIRE(arr == obj["hello"].as<const JsonArray>());
-    REQUIRE(&arr == &obj["hello"].as<const JsonArray>());  // <- short hand
+    // REQUIRE(arr == obj["hello"].as<const JsonArray>());  // <- short hand
-    REQUIRE(true == obj["hello"].is<JsonArray&>());
+    REQUIRE(true == obj["hello"].is<JsonArray>());
     REQUIRE(true == obj["hello"].is<JsonArray>());
-    REQUIRE(true == obj["hello"].is<const JsonArray&>());
     REQUIRE(true == obj["hello"].is<const JsonArray>());
-    REQUIRE(false == obj["hello"].is<JsonObject&>());
+    REQUIRE(true == obj["hello"].is<const JsonArray>());
+    REQUIRE(false == obj["hello"].is<JsonObject>());
   }
 
   SECTION("object") {
     DynamicJsonDocument doc2;
-    JsonObject& obj2 = doc2.to<JsonObject>();
+    JsonObject obj2 = doc2.to<JsonObject>();
 
     obj["hello"] = obj2;
 
-    REQUIRE(&obj2 == &obj["hello"].as<JsonObject&>());
+    REQUIRE(obj2 == obj["hello"].as<JsonObject>());
-    REQUIRE(&obj2 == &obj["hello"].as<JsonObject>());  // <- short hand
+    REQUIRE(obj2 == obj["hello"].as<const JsonObject>());
-    REQUIRE(&obj2 == &obj["hello"].as<const JsonObject&>());
-    REQUIRE(&obj2 == &obj["hello"].as<const JsonObject>());  // <- short hand
-    REQUIRE(true == obj["hello"].is<JsonObject&>());
     REQUIRE(true == obj["hello"].is<JsonObject>());
-    REQUIRE(true == obj["hello"].is<const JsonObject&>());
     REQUIRE(true == obj["hello"].is<const JsonObject>());
-    REQUIRE(false == obj["hello"].is<JsonArray&>());
+    REQUIRE(false == obj["hello"].is<JsonArray>());
   }
 
   SECTION("array subscript") {
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
     arr.add(42);
 
     obj["a"] = arr[0];
@@ -97,7 +93,7 @@ TEST_CASE("JsonObject::operator[]") {
 
   SECTION("object subscript") {
     DynamicJsonDocument doc2;
-    JsonObject& obj2 = doc2.to<JsonObject>();
+    JsonObject obj2 = doc2.to<JsonObject>();
     obj2.set("x", 42);
 
     obj["a"] = obj2["x"];

test/JsonSerializer/JsonArray.cpp

@@ -5,7 +5,7 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-static void check(JsonArray &array, std::string expected) {
+static void check(JsonArray array, std::string expected) {
   std::string actual;
   size_t actualLen = serializeJson(array, actual);
   REQUIRE(expected == actual);
@@ -16,7 +16,7 @@ static void check(JsonArray &array, std::string expected) {
 
 TEST_CASE("serializeJson(JsonArray)") {
   StaticJsonDocument<JSON_ARRAY_SIZE(2)> doc;
-  JsonArray &array = doc.to<JsonArray>();
+  JsonArray array = doc.to<JsonArray>();
 
   SECTION("Empty") {
     check(array, "[]");

test/JsonSerializer/JsonArrayPretty.cpp

@@ -5,7 +5,7 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-static void check(JsonArray& array, std::string expected) {
+static void check(JsonArray array, std::string expected) {
   std::string actual;
   size_t actualLen = serializeJsonPretty(array, actual);
   size_t measuredLen = measureJsonPretty(array);
@@ -16,7 +16,7 @@ static void check(JsonArray& array, std::string expected) {
 
 TEST_CASE("serializeJsonPretty(JsonArray)") {
   DynamicJsonDocument doc;
-  JsonArray& array = doc.to<JsonArray>();
+  JsonArray array = doc.to<JsonArray>();
 
   SECTION("Empty") {
     check(array, "[]");
@@ -54,11 +54,11 @@ TEST_CASE("serializeJsonPretty(JsonArray)") {
   }
 
   SECTION("NestedArrays") {
-    JsonArray& nested1 = array.createNestedArray();
+    JsonArray nested1 = array.createNestedArray();
     nested1.add(1);
     nested1.add(2);
 
-    JsonObject& nested2 = array.createNestedObject();
+    JsonObject nested2 = array.createNestedObject();
     nested2["key"] = 3;
 
     check(array,

test/JsonSerializer/JsonObject.cpp

@@ -6,7 +6,7 @@
 #include <catch.hpp>
 #include <string>
 
-void check(const JsonObject &obj, const std::string &expected) {
+void check(const JsonObject obj, const std::string &expected) {
   char actual[256];
   size_t actualLen = serializeJson(obj, actual);
   size_t measuredLen = measureJson(obj);
@@ -18,7 +18,7 @@ void check(const JsonObject &obj, const std::string &expected) {
 
 TEST_CASE("serializeJson(JsonObject)") {
   DynamicJsonDocument doc;
-  JsonObject &obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
 
   SECTION("EmptyObject") {
     check(obj, "{}");

test/JsonSerializer/JsonObjectPretty.cpp

@@ -6,7 +6,7 @@
 #include <catch.hpp>
 #include <string>
 
-void check(const JsonObject &obj, const std::string expected) {
+void check(const JsonObject obj, const std::string expected) {
   char json[256];
 
   size_t actualLen = serializeJsonPretty(obj, json);
@@ -19,7 +19,7 @@ void check(const JsonObject &obj, const std::string expected) {
 
 TEST_CASE("serializeJsonPretty(JsonObject)") {
   DynamicJsonDocument doc;
-  JsonObject &obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
 
   SECTION("EmptyObject") {
     check(obj, "{}");
@@ -57,10 +57,10 @@ TEST_CASE("serializeJsonPretty(JsonObject)") {
   }
 
   SECTION("NestedContainers") {
-    JsonObject &nested1 = obj.createNestedObject("key1");
+    JsonObject nested1 = obj.createNestedObject("key1");
     nested1["a"] = 1;
 
-    JsonArray &nested2 = obj.createNestedArray("key2");
+    JsonArray nested2 = obj.createNestedArray("key2");
     nested2.add(2);
 
     check(obj,

test/JsonSerializer/JsonVariant.cpp

@@ -14,11 +14,11 @@ void check(JsonVariant variant, const std::string &expected) {
 }
 
 TEST_CASE("serializeJson(JsonVariant)") {
-  SECTION("Empty") {
+  SECTION("Undefined") {
-    check(JsonVariant(), "");
+    check(JsonVariant(), "null");
   }
 
-  SECTION("Null") {
+  SECTION("Null string") {
     check(static_cast<char *>(0), "null");
   }
 

test/JsonSerializer/std_stream.cpp

@@ -27,7 +27,7 @@ TEST_CASE("operator<<(std::ostream)") {
   }
 
   SECTION("JsonObject") {
-    JsonObject& object = doc.to<JsonObject>();
+    JsonObject object = doc.to<JsonObject>();
     object["key"] = "value";
 
     os << object;
@@ -36,7 +36,7 @@ TEST_CASE("operator<<(std::ostream)") {
   }
 
   SECTION("JsonObjectSubscript") {
-    JsonObject& object = doc.to<JsonObject>();
+    JsonObject object = doc.to<JsonObject>();
     object["key"] = "value";
 
     os << object["key"];
@@ -45,7 +45,7 @@ TEST_CASE("operator<<(std::ostream)") {
   }
 
   SECTION("JsonArray") {
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
     array.add("value");
 
     os << array;
@@ -54,7 +54,7 @@ TEST_CASE("operator<<(std::ostream)") {
   }
 
   SECTION("JsonArraySubscript") {
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
     array.add("value");
 
     os << array[0];

test/JsonSerializer/std_string.cpp

@@ -7,7 +7,7 @@
 
 TEST_CASE("serialize JsonArray to std::string") {
   DynamicJsonDocument doc;
-  JsonArray &array = doc.to<JsonArray>();
+  JsonArray array = doc.to<JsonArray>();
   array.add(4);
   array.add(2);
 
@@ -28,7 +28,7 @@ TEST_CASE("serialize JsonArray to std::string") {
 
 TEST_CASE("serialize JsonObject to std::string") {
   DynamicJsonDocument doc;
-  JsonObject &obj = doc.to<JsonObject>();
+  JsonObject obj = doc.to<JsonObject>();
   obj["key"] = "value";
 
   SECTION("object") {

test/JsonVariant/CMakeLists.txt

@@ -7,10 +7,10 @@ add_executable(JsonVariantTests
 	compare.cpp
 	copy.cpp
 	is.cpp
+	isnull.cpp
 	or.cpp
 	set_get.cpp
 	subscript.cpp
-	success.cpp
 	undefined.cpp
 )
 

test/JsonVariant/as.cpp

@@ -193,7 +193,7 @@ TEST_CASE("JsonVariant::as()") {
 
   SECTION("ObjectAsString") {
     DynamicJsonDocument doc;
-    JsonObject& obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
 
     obj["key"] = "value";
 
@@ -203,7 +203,7 @@ TEST_CASE("JsonVariant::as()") {
 
   SECTION("ArrayAsString") {
     DynamicJsonDocument doc;
-    JsonArray& arr = doc.to<JsonArray>();
+    JsonArray arr = doc.to<JsonArray>();
     arr.add(4);
     arr.add(2);
 
@@ -213,19 +213,19 @@ TEST_CASE("JsonVariant::as()") {
 
   SECTION("ArrayAsJsonArray") {
     DynamicJsonDocument doc;
-    JsonArray& arr = doc.to<JsonArray>();
+    JsonArray arr = doc.to<JsonArray>();
 
     JsonVariant variant = arr;
-    REQUIRE(&arr == &variant.as<JsonArray&>());
+    REQUIRE(arr == variant.as<JsonArray>());
-    REQUIRE(&arr == &variant.as<JsonArray>());  // <- shorthand
+    REQUIRE(arr == variant.as<JsonArray>());  // <- shorthand
   }
 
   SECTION("ObjectAsJsonObject") {
     DynamicJsonDocument doc;
-    JsonObject& obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
 
     JsonVariant variant = obj;
-    REQUIRE(&obj == &variant.as<JsonObject&>());
+    REQUIRE(obj == variant.as<JsonObject>());
-    REQUIRE(&obj == &variant.as<JsonObject>());  // <- shorthand
+    REQUIRE(obj == variant.as<JsonObject>());  // <- shorthand
   }
 }

test/JsonVariant/compare.cpp

@@ -213,9 +213,9 @@ TEST_CASE("JsonVariant comparisons") {
 
   SECTION("ArrayInVariant") {
     DynamicJsonDocument doc1;
-    JsonArray& array1 = doc1.to<JsonArray>();
+    JsonArray array1 = doc1.to<JsonArray>();
     DynamicJsonDocument doc2;
-    JsonArray& array2 = doc2.to<JsonArray>();
+    JsonArray array2 = doc2.to<JsonArray>();
 
     JsonVariant variant1 = array1;
     JsonVariant variant2 = array1;
@@ -230,9 +230,9 @@ TEST_CASE("JsonVariant comparisons") {
 
   SECTION("ObjectInVariant") {
     DynamicJsonDocument doc1;
-    JsonObject& obj1 = doc1.to<JsonObject>();
+    JsonObject obj1 = doc1.to<JsonObject>();
     DynamicJsonDocument doc2;
-    JsonObject& obj2 = doc2.to<JsonObject>();
+    JsonObject obj2 = doc2.to<JsonObject>();
 
     JsonVariant variant1 = obj1;
     JsonVariant variant2 = obj1;
@@ -247,10 +247,10 @@ TEST_CASE("JsonVariant comparisons") {
 
   SECTION("VariantsOfDifferentTypes") {
     DynamicJsonDocument doc1;
-    JsonObject& obj = doc1.to<JsonObject>();
+    JsonObject obj = doc1.to<JsonObject>();
 
     DynamicJsonDocument doc2;
-    JsonArray& arr = doc2.to<JsonArray>();
+    JsonArray arr = doc2.to<JsonArray>();
     JsonVariant variants[] = {
         true, 42, 666.667, "hello", arr, obj,
     };

test/JsonVariant/copy.cpp

@@ -43,7 +43,7 @@ TEST_CASE("JsonVariant copy") {
 
   SECTION("ObjectsAreCopiedByReference") {
     DynamicJsonDocument doc;
-    JsonObject& object = doc.to<JsonObject>();
+    JsonObject object = doc.to<JsonObject>();
 
     _variant1 = object;
 
@@ -54,7 +54,7 @@ TEST_CASE("JsonVariant copy") {
 
   SECTION("ArraysAreCopiedByReference") {
     DynamicJsonDocument doc;
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
 
     _variant1 = array;
 

test/JsonVariant/is.cpp

@@ -7,9 +7,9 @@
 
 void checkIsArray(JsonVariant var) {
   REQUIRE(var.is<JsonArray>());
-  REQUIRE(var.is<JsonArray&>());
+  REQUIRE(var.is<JsonArray>());
+  REQUIRE(var.is<const JsonArray>());
   REQUIRE(var.is<const JsonArray>());
-  REQUIRE(var.is<const JsonArray&>());
 
   REQUIRE_FALSE(var.is<bool>());
   REQUIRE_FALSE(var.is<double>());
@@ -71,7 +71,7 @@ void checkIsString(JsonVariant var) {
 TEST_CASE("JsonVariant::is()") {
   SECTION("JsonArray") {
     DynamicJsonDocument doc;
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
     checkIsArray(array);
   }
 

test/JsonVariant/isnull.cpp

@@ -5,40 +5,40 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-TEST_CASE("JsonVariant::success()") {
+TEST_CASE("JsonVariant::isNull()") {
   SECTION("ReturnsFalse_WhenUndefined") {
     JsonVariant variant;
-    REQUIRE(false == variant.success());
+    REQUIRE(variant.isNull() == true);
   }
 
   SECTION("ReturnsTrue_WhenInteger") {
     JsonVariant variant = 0;
-    REQUIRE(true == variant.success());
+    REQUIRE(variant.isNull() == false);
   }
 
   SECTION("ReturnsTrue_WhenEmptyArray") {
     DynamicJsonDocument doc;
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
 
     JsonVariant variant = array;
-    REQUIRE(true == variant.success());
+    REQUIRE(variant.isNull() == false);
   }
 
   SECTION("ReturnsTrue_WhenEmptyObject") {
     DynamicJsonDocument doc;
-    JsonObject& obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
 
     JsonVariant variant = obj;
-    REQUIRE(true == variant.success());
+    REQUIRE(variant.isNull() == false);
   }
 
   SECTION("ReturnsFalse_WhenInvalidArray") {
-    JsonVariant variant = JsonArray::invalid();
+    JsonVariant variant = JsonArray();
-    REQUIRE(false == variant.success());
+    REQUIRE(variant.isNull() == true);
   }
 
   SECTION("ReturnsFalse_WhenInvalidObject") {
-    JsonVariant variant = JsonObject::invalid();
+    JsonVariant variant = JsonObject();
-    REQUIRE(false == variant.success());
+    REQUIRE(variant.isNull() == true);
   }
 }

test/JsonVariant/set_get.cpp

@@ -123,8 +123,8 @@ TEST_CASE("JsonVariant set()/get()") {
 
   SECTION("CanStoreObject") {
     DynamicJsonDocument doc;
-    JsonObject &object = doc.to<JsonObject>();
+    JsonObject object = doc.to<JsonObject>();
 
-    checkReference<JsonObject>(object);
+    checkValue<JsonObject>(object);
   }
 }

test/JsonVariant/subscript.cpp

@@ -8,7 +8,7 @@
 TEST_CASE("JsonVariant::operator[]") {
   SECTION("Array") {
     DynamicJsonDocument doc;
-    JsonArray& array = doc.to<JsonArray>();
+    JsonArray array = doc.to<JsonArray>();
     array.add("element at index 0");
     array.add("element at index 1");
 
@@ -19,14 +19,14 @@ TEST_CASE("JsonVariant::operator[]") {
     REQUIRE(std::string("element at index 1") == var[1]);
     REQUIRE(std::string("element at index 0") ==
             var[static_cast<unsigned char>(0)]);  // issue #381
-    REQUIRE_FALSE(var[666].success());
+    REQUIRE(var[666].isNull());
-    REQUIRE_FALSE(var[3].success());
+    REQUIRE(var[3].isNull());
-    REQUIRE_FALSE(var["0"].success());
+    REQUIRE(var["0"].isNull());
   }
 
   SECTION("Object") {
     DynamicJsonDocument doc;
-    JsonObject& object = doc.to<JsonObject>();
+    JsonObject object = doc.to<JsonObject>();
     object["a"] = "element at key \"a\"";
     object["b"] = "element at key \"b\"";
 
@@ -35,27 +35,27 @@ TEST_CASE("JsonVariant::operator[]") {
     REQUIRE(2 == var.size());
     REQUIRE(std::string("element at key \"a\"") == var["a"]);
     REQUIRE(std::string("element at key \"b\"") == var["b"]);
-    REQUIRE_FALSE(var["c"].success());
+    REQUIRE(var["c"].isNull());
-    REQUIRE_FALSE(var[0].success());
+    REQUIRE(var[0].isNull());
   }
 
   SECTION("Undefined") {
     JsonVariant var = JsonVariant();
     REQUIRE(0 == var.size());
-    REQUIRE_FALSE(var["0"].success());
+    REQUIRE(var["0"].isNull());
-    REQUIRE_FALSE(var[0].success());
+    REQUIRE(var[0].isNull());
   }
 
   SECTION("String") {
     JsonVariant var = "hello world";
     REQUIRE(0 == var.size());
-    REQUIRE_FALSE(var["0"].success());
+    REQUIRE(var["0"].isNull());
-    REQUIRE_FALSE(var[0].success());
+    REQUIRE(var[0].isNull());
   }
 
   SECTION("ObjectSetValue") {
     DynamicJsonDocument doc;
-    JsonObject& obj = doc.to<JsonObject>();
+    JsonObject obj = doc.to<JsonObject>();
     JsonVariant var = obj;
     var["hello"] = "world";
     REQUIRE(1 == var.size());
@@ -64,7 +64,7 @@ TEST_CASE("JsonVariant::operator[]") {
 
   SECTION("ArraySetValue") {
     DynamicJsonDocument doc;
-    JsonArray& arr = doc.to<JsonArray>();
+    JsonArray arr = doc.to<JsonArray>();
     arr.add("hello");
     JsonVariant var = arr;
     var[0] = "world";

test/JsonVariant/undefined.cpp

@@ -29,26 +29,26 @@ TEST_CASE("JsonVariant undefined") {
   }
 
   SECTION("AsArrayReturnInvalid") {
-    REQUIRE(JsonArray::invalid() == variant.as<JsonArray&>());
+    REQUIRE(JsonArray() == variant.as<JsonArray>());
   }
 
   SECTION("AsConstArrayReturnInvalid") {
-    REQUIRE(JsonArray::invalid() == variant.as<const JsonArray&>());
+    REQUIRE(JsonArray() == variant.as<const JsonArray>());
   }
 
   SECTION("AsObjectReturnInvalid") {
-    REQUIRE(JsonObject::invalid() == variant.as<JsonObject&>());
+    REQUIRE(JsonObject() == variant.as<JsonObject>());
   }
 
   SECTION("AsConstObjectReturnInvalid") {
-    REQUIRE(JsonObject::invalid() == variant.as<const JsonObject&>());
+    REQUIRE(JsonObject() == variant.as<const JsonObject>());
   }
 
   SECTION("AsArrayWrapperReturnInvalid") {
-    REQUIRE(JsonArray::invalid() == variant.as<JsonArray>());
+    REQUIRE(JsonArray() == variant.as<JsonArray>());
   }
 
   SECTION("AsObjectWrapperReturnInvalid") {
-    REQUIRE(JsonObject::invalid() == variant.as<JsonObject>());
+    REQUIRE(JsonObject() == variant.as<JsonObject>());
   }
 }

test/Misc/unsigned_char.cpp

@@ -101,7 +101,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char key[] = "hello";
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj[key] = "world";
 
       REQUIRE(std::string("world") == obj["hello"]);
@@ -113,7 +113,7 @@ TEST_CASE("unsigned char[]") {
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":\"world\"}");
 
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
       REQUIRE(std::string("world") == obj[key]);
     }
 #endif
@@ -123,7 +123,7 @@ TEST_CASE("unsigned char[]") {
 
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
       REQUIRE(std::string("world") == obj.get<char*>(key));
     }
 
@@ -131,7 +131,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char key[] = "hello";
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.set(key, "world");
 
       REQUIRE(std::string("world") == obj["hello"]);
@@ -141,7 +141,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char value[] = "world";
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.set("hello", value);
 
       REQUIRE(std::string("world") == obj["hello"]);
@@ -151,7 +151,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char key[] = "world";
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.set(key, key);
 
       REQUIRE(std::string("world") == obj["world"]);
@@ -162,7 +162,7 @@ TEST_CASE("unsigned char[]") {
 
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
       REQUIRE(true == obj.containsKey(key));
     }
 
@@ -171,7 +171,7 @@ TEST_CASE("unsigned char[]") {
 
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
       obj.remove(key);
 
       REQUIRE(0 == obj.size());
@@ -182,7 +182,7 @@ TEST_CASE("unsigned char[]") {
 
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":42}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(true == obj.is<int>(key));
     }
@@ -191,7 +191,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char key[] = "hello";
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.createNestedArray(key);
     }
 
@@ -199,7 +199,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char key[] = "hello";
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.createNestedObject(key);
     }
   }
@@ -209,7 +209,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char value[] = "world";
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj["hello"] = value;
 
       REQUIRE(std::string("world") == obj["hello"]);
@@ -219,7 +219,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char value[] = "world";
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj["hello"].set(value);
 
       REQUIRE(std::string("world") == obj["hello"]);
@@ -231,7 +231,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char value[] = "world";
 
       DynamicJsonDocument doc;
-      JsonArray& arr = doc.to<JsonArray>();
+      JsonArray arr = doc.to<JsonArray>();
       arr.add(value);
 
       REQUIRE(std::string("world") == arr[0]);
@@ -241,7 +241,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char value[] = "world";
 
       DynamicJsonDocument doc;
-      JsonArray& arr = doc.to<JsonArray>();
+      JsonArray arr = doc.to<JsonArray>();
       arr.add("hello");
       arr.set(0, value);
 
@@ -254,7 +254,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char value[] = "world";
 
       DynamicJsonDocument doc;
-      JsonArray& arr = doc.to<JsonArray>();
+      JsonArray arr = doc.to<JsonArray>();
       arr.add("hello");
       arr[0].set(value);
 
@@ -265,7 +265,7 @@ TEST_CASE("unsigned char[]") {
       unsigned char value[] = "world";
 
       DynamicJsonDocument doc;
-      JsonArray& arr = doc.to<JsonArray>();
+      JsonArray arr = doc.to<JsonArray>();
       arr.add("hello");
       arr[0] = value;
 

test/Misc/vla.cpp

@@ -126,7 +126,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "hello");
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj[vla] = "world";
 
       REQUIRE(std::string("world") == obj["hello"]);
@@ -142,7 +142,7 @@ TEST_CASE("Variable Length Array") {
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":\"world\"}");
 
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
       REQUIRE(std::string("world") == obj[vla]);
     }
 #endif
@@ -155,7 +155,7 @@ TEST_CASE("Variable Length Array") {
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":\"world\"}");
 
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
       REQUIRE(std::string("world") == obj.get<char*>(vla));
     }
 
@@ -165,7 +165,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "hello");
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.set(vla, "world");
 
       REQUIRE(std::string("world") == obj["hello"]);
@@ -177,7 +177,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "world");
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.set("hello", vla);
 
       REQUIRE(std::string("world") == obj["hello"]);
@@ -189,7 +189,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "world");
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.set(vla, vla);
 
       REQUIRE(std::string("world") == obj["world"]);
@@ -203,7 +203,7 @@ TEST_CASE("Variable Length Array") {
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":\"world\"}");
 
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
       REQUIRE(true == obj.containsKey(vla));
     }
 
@@ -214,7 +214,7 @@ TEST_CASE("Variable Length Array") {
 
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":\"world\"}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
       obj.remove(vla);
 
       REQUIRE(0 == obj.size());
@@ -227,7 +227,7 @@ TEST_CASE("Variable Length Array") {
 
       DynamicJsonDocument doc;
       deserializeJson(doc, "{\"hello\":42}");
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(true == obj.is<int>(vla));
     }
@@ -238,7 +238,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "hello");
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.createNestedArray(vla);
     }
 
@@ -248,7 +248,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "hello");
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj.createNestedObject(vla);
     }
   }
@@ -260,7 +260,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "world");
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj["hello"] = vla;
 
       REQUIRE(std::string("world") == obj["hello"].as<char*>());
@@ -272,7 +272,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "world");
 
       DynamicJsonDocument doc;
-      JsonObject& obj = doc.to<JsonObject>();
+      JsonObject obj = doc.to<JsonObject>();
       obj["hello"].set(vla);
 
       REQUIRE(std::string("world") == obj["hello"].as<char*>());
@@ -286,7 +286,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "world");
 
       DynamicJsonDocument doc;
-      JsonArray& arr = doc.to<JsonArray>();
+      JsonArray arr = doc.to<JsonArray>();
       arr.add(vla);
 
       REQUIRE(std::string("world") == arr[0]);
@@ -298,7 +298,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "world");
 
       DynamicJsonDocument doc;
-      JsonArray& arr = doc.to<JsonArray>();
+      JsonArray arr = doc.to<JsonArray>();
       arr.add("hello");
       arr.set(0, vla);
 
@@ -313,7 +313,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "world");
 
       DynamicJsonDocument doc;
-      JsonArray& arr = doc.to<JsonArray>();
+      JsonArray arr = doc.to<JsonArray>();
       arr.add("hello");
       arr[0].set(vla);
 
@@ -326,7 +326,7 @@ TEST_CASE("Variable Length Array") {
       strcpy(vla, "world");
 
       DynamicJsonDocument doc;
-      JsonArray& arr = doc.to<JsonArray>();
+      JsonArray arr = doc.to<JsonArray>();
       arr.add("hello");
       arr[0] = vla;
 

test/MsgPackDeserializer/deserializeArray.cpp

@@ -13,7 +13,7 @@ TEST_CASE("deserialize MsgPack array") {
       const char* input = "\x90";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonArray& array = doc.as<JsonArray>();
+      JsonArray array = doc.as<JsonArray>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(array.size() == 0);
@@ -23,7 +23,7 @@ TEST_CASE("deserialize MsgPack array") {
       const char* input = "\x92\x01\x02";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonArray& array = doc.as<JsonArray>();
+      JsonArray array = doc.as<JsonArray>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(array.size() == 2);
@@ -37,7 +37,7 @@ TEST_CASE("deserialize MsgPack array") {
       const char* input = "\xDC\x00\x00";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonArray& array = doc.as<JsonArray>();
+      JsonArray array = doc.as<JsonArray>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(array.size() == 0);
@@ -47,7 +47,7 @@ TEST_CASE("deserialize MsgPack array") {
       const char* input = "\xDC\x00\x02\xA5hello\xA5world";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonArray& array = doc.as<JsonArray>();
+      JsonArray array = doc.as<JsonArray>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(array.size() == 2);
@@ -61,7 +61,7 @@ TEST_CASE("deserialize MsgPack array") {
       const char* input = "\xDD\x00\x00\x00\x00";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonArray& array = doc.as<JsonArray>();
+      JsonArray array = doc.as<JsonArray>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(array.size() == 0);
@@ -72,7 +72,7 @@ TEST_CASE("deserialize MsgPack array") {
           "\xDD\x00\x00\x00\x02\xCA\x00\x00\x00\x00\xCA\x40\x48\xF5\xC3";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonArray& array = doc.as<JsonArray>();
+      JsonArray array = doc.as<JsonArray>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(array.size() == 2);

test/MsgPackDeserializer/deserializeObject.cpp

@@ -13,7 +13,7 @@ TEST_CASE("deserialize MsgPack object") {
       const char* input = "\x80";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -24,7 +24,7 @@ TEST_CASE("deserialize MsgPack object") {
       const char* input = "\x82\xA3one\x01\xA3two\x02";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -39,7 +39,7 @@ TEST_CASE("deserialize MsgPack object") {
       const char* input = "\xDE\x00\x00";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -50,7 +50,7 @@ TEST_CASE("deserialize MsgPack object") {
       const char* input = "\xDE\x00\x02\xA1H\xA5hello\xA1W\xA5world";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -65,7 +65,7 @@ TEST_CASE("deserialize MsgPack object") {
       const char* input = "\xDF\x00\x00\x00\x00";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
@@ -78,7 +78,7 @@ TEST_CASE("deserialize MsgPack object") {
           "\xF5\xC3";
 
       DeserializationError error = deserializeMsgPack(doc, input);
-      JsonObject& obj = doc.as<JsonObject>();
+      JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(error == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());

test/MsgPackDeserializer/std_istream.cpp

@@ -14,7 +14,7 @@ TEST_CASE("deserializeMsgPack(std::istream&)") {
     DeserializationError err = deserializeMsgPack(doc, input);
 
     REQUIRE(err == DeserializationError::Ok);
-    JsonArray& arr = doc.as<JsonArray>();
+    JsonArray arr = doc.as<JsonArray>();
     REQUIRE(arr[0] == 0);
     REQUIRE(arr[1] == 2);
   }

test/MsgPackDeserializer/std_string.cpp

@@ -29,7 +29,7 @@ TEST_CASE("deserializeMsgPack(const std::string&)") {
     DeserializationError err = deserializeMsgPack(doc, input);
     input[2] = 'X';  // alter the string tomake sure we made a copy
 
-    JsonArray& array = doc.as<JsonArray>();
+    JsonArray array = doc.as<JsonArray>();
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(std::string("hello") == array[0]);
   }
@@ -39,7 +39,7 @@ TEST_CASE("deserializeMsgPack(const std::string&)") {
         deserializeMsgPack(doc, std::string("\x92\x00\x02", 3));
 
     REQUIRE(err == DeserializationError::Ok);
-    JsonArray& arr = doc.as<JsonArray>();
+    JsonArray arr = doc.as<JsonArray>();
     REQUIRE(arr[0] == 0);
     REQUIRE(arr[1] == 2);
   }

test/MsgPackSerializer/destination_types.cpp

@@ -7,7 +7,7 @@
 
 TEST_CASE("serialize MsgPack to various destination types") {
   DynamicJsonDocument doc;
-  JsonObject &object = doc.to<JsonObject>();
+  JsonObject object = doc.to<JsonObject>();
   object["hello"] = "world";
   const char *expected_result = "\x81\xA5hello\xA5world";
   const size_t expected_length = 13;

test/MsgPackSerializer/measure.cpp

@@ -7,7 +7,7 @@
 
 TEST_CASE("measureMsgPack()") {
   DynamicJsonDocument doc;
-  JsonObject &object = doc.to<JsonObject>();
+  JsonObject object = doc.to<JsonObject>();
   object["hello"] = "world";
 
   REQUIRE(measureMsgPack(doc) == 13);

test/MsgPackSerializer/serializeArray.cpp

@@ -5,7 +5,7 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-static void check(const JsonArray& array, const char* expected_data,
+static void check(const JsonArray array, const char* expected_data,
                   size_t expected_len) {
   std::string expected(expected_data, expected_data + expected_len);
   std::string actual;
@@ -16,19 +16,19 @@ static void check(const JsonArray& array, const char* expected_data,
 }
 
 template <size_t N>
-static void check(const JsonArray& array, const char (&expected_data)[N]) {
+static void check(const JsonArray array, const char (&expected_data)[N]) {
   const size_t expected_len = N - 1;
   check(array, expected_data, expected_len);
 }
 
 // TODO: this function is used by the commented test
-// static void check(const JsonArray& array, const std::string& expected) {
+// static void check(const JsonArray array, const std::string& expected) {
 //   check(array, expected.data(), expected.length());
 // }
 
 TEST_CASE("serialize MsgPack array") {
   DynamicJsonDocument doc;
-  JsonArray& array = doc.to<JsonArray>();
+  JsonArray array = doc.to<JsonArray>();
 
   SECTION("empty") {
     check(array, "\x90");

test/MsgPackSerializer/serializeObject.cpp

@@ -6,7 +6,7 @@
 #include <stdio.h>
 #include <catch.hpp>
 
-static void check(const JsonObject& object, const char* expected_data,
+static void check(const JsonObject object, const char* expected_data,
                   size_t expected_len) {
   std::string expected(expected_data, expected_data + expected_len);
   std::string actual;
@@ -17,19 +17,19 @@ static void check(const JsonObject& object, const char* expected_data,
 }
 
 template <size_t N>
-static void check(const JsonObject& object, const char (&expected_data)[N]) {
+static void check(const JsonObject object, const char (&expected_data)[N]) {
   const size_t expected_len = N - 1;
   check(object, expected_data, expected_len);
 }
 
 // TODO: used by the commented test
-// static void check(const JsonObject& object, const std::string& expected) {
+// static void check(const JsonObject object, const std::string& expected) {
 //  check(object, expected.data(), expected.length());
 //}
 
 TEST_CASE("serialize MsgPack object") {
   DynamicJsonDocument doc;
-  JsonObject& object = doc.to<JsonObject>();
+  JsonObject object = doc.to<JsonObject>();
 
   SECTION("empty") {
     check(object, "\x80");