diff --git a/include/ArduinoJson/JsonArray.hpp b/include/ArduinoJson/JsonArray.hpp
index 88bde904..0d944ef6 100644
--- a/include/ArduinoJson/JsonArray.hpp
+++ b/include/ArduinoJson/JsonArray.hpp
@@ -14,16 +14,16 @@
 
 namespace ArduinoJson {
 class JsonArray : public JsonPrintable {
+  friend class JsonBuffer;
+
  public:
   typedef JsonValue value_type;
   typedef JsonArrayIterator iterator;
   typedef JsonArrayConstIterator const_iterator;
 
-  JsonArray(JsonBuffer *buffer = NULL) : _buffer(buffer), _firstNode(NULL) {}
-
   int size() const;
 
-  bool success() {return _buffer != NULL;}
+  bool success() { return _buffer != NULL; }
 
   value_type &operator[](int index) const;
   value_type &add();
@@ -33,13 +33,9 @@ class JsonArray : public JsonPrintable {
     add().set(value);
   }
 
-  void add(JsonArray &nestedArray) {
-    add().set(nestedArray);
-  }
-
-  void add(JsonObject&nestedObject){
-    add().set(nestedObject);
-  }
+  void add(double value, int decimals) { add().set(value, decimals); }
+  void add(JsonArray &nestedArray) { add().set(nestedArray); }
+  void add(JsonObject &nestedObject) { add().set(nestedObject); }
 
   JsonArray &createNestedArray();
   JsonObject &createNestedObject();
@@ -55,8 +51,12 @@ class JsonArray : public JsonPrintable {
   virtual void writeTo(Internals::JsonWriter &writer) const;
 
  private:
-  JsonArray(const JsonArray&); // copy is forbidden, use a reference instead
-  JsonArray& operator=(const JsonArray&); // copy is forbidden, use a reference instead
+  // constructor is private: instance must be created via a JsonBuffer
+  JsonArray(JsonBuffer *buffer) : _buffer(buffer), _firstNode(NULL) {}
+
+  JsonArray(const JsonArray &);  // copy is forbidden, use a reference instead
+  JsonArray &operator=(
+      const JsonArray &);  // copy is forbidden, use a reference instead
 
   inline void addNode(Internals::JsonArrayNode *node);
 
diff --git a/include/ArduinoJson/JsonObject.hpp b/include/ArduinoJson/JsonObject.hpp
index 9bfc8b59..cff469e3 100644
--- a/include/ArduinoJson/JsonObject.hpp
+++ b/include/ArduinoJson/JsonObject.hpp
@@ -14,14 +14,14 @@
 
 namespace ArduinoJson {
 class JsonObject : public JsonPrintable {
+  friend class JsonBuffer;
+
  public:
   typedef const char *key_type;
   typedef JsonPair value_type;
   typedef JsonObjectIterator iterator;
   typedef JsonObjectConstIterator const_iterator;
 
-  JsonObject(JsonBuffer *buffer) : _buffer(buffer), _firstNode(NULL) {}
-
   int size() const;
 
   JsonValue &operator[](key_type key);
@@ -29,16 +29,11 @@ class JsonObject : public JsonPrintable {
 
   template <typename T>
   void add(key_type key, T value) {
-    (*this)[key] = value;
+    add(key).set(value);
   }
 
-  void add(key_type key, JsonArray &nestedArray) {
-    (*this)[key] = nestedArray;
-  }
-
-  void add(key_type key, JsonObject &nestedObject) {
-    (*this)[key] = nestedObject;
-  }
+  void add(key_type key, JsonArray &array) { add(key).set(array); }
+  void add(key_type key, JsonObject &object) { add(key).set(object); }
 
   JsonArray &createNestedArray(key_type key);
   JsonObject &createNestedObject(key_type key);
@@ -54,9 +49,14 @@ class JsonObject : public JsonPrintable {
   virtual void writeTo(Internals::JsonWriter &writer) const;
 
  private:
-  JsonObject(const JsonObject&); // copy is forbidden, use a reference instead
-  JsonObject& operator=(const JsonObject&); // copy is forbidden, use a reference instead
+  // constructor is private, instance must be created via JsonBuffer
+  JsonObject(JsonBuffer *buffer) : _buffer(buffer), _firstNode(NULL) {}
 
+  JsonObject(const JsonObject &);  // copy is forbidden, use a reference instead
+  JsonObject &operator=(
+      const JsonObject &);  // copy is forbidden, use a reference instead
+
+  JsonValue &add(key_type key) { return (*this)[key]; }
   void addNode(Internals::JsonObjectNode *nodeToAdd);
   void removeNode(Internals::JsonObjectNode *nodeToRemove);
 
diff --git a/include/ArduinoJson/JsonValue.hpp b/include/ArduinoJson/JsonValue.hpp
index 4f598bee..df90a9be 100644
--- a/include/ArduinoJson/JsonValue.hpp
+++ b/include/ArduinoJson/JsonValue.hpp
@@ -32,25 +32,30 @@ class JsonValue {
     return *this;
   }
 
-  JsonValue &operator=(JsonArray& array) {
+  JsonValue &operator=(JsonArray &array) {
     set(array);
     return *this;
   }
 
-  JsonValue &operator=(JsonObject& object) {
+  JsonValue &operator=(JsonObject &object) {
     set(object);
     return *this;
   }
 
-  JsonArray &asArray();
-  JsonObject &asObject();
-  bool asBool() const;
-  const char *asString() const;
-  double asDouble() const;
-  long asLong() const;
+  operator bool() const;
+  operator const char *() const;
+  operator double() const;
+  operator long() const;
+  operator JsonArray &() const;
+  operator JsonObject &() const;
+
+  JsonArray &asArray() { return static_cast<JsonArray &>(*this); };
+  JsonObject &asObject() { return static_cast<JsonObject &>(*this); };
 
   template <typename T>
-  T as(){}
+  T as() {
+    return static_cast<T>(*this);
+  }
 
   static JsonValue &invalid() { return _invalid; }
 
@@ -63,8 +68,3 @@ class JsonValue {
   Internals::JsonValueContent _content;
   static JsonValue _invalid;
 };
-
-template <>
-int JsonValue::as<int>() { return asLong(); }
-
-}
diff --git a/src/JsonValue.cpp b/src/JsonValue.cpp
index 4d64b221..06cb26b9 100644
--- a/src/JsonValue.cpp
+++ b/src/JsonValue.cpp
@@ -12,27 +12,27 @@
 using namespace ArduinoJson;
 using namespace ArduinoJson::Internals;
 
-JsonArray &JsonValue::asArray() {
+JsonValue::operator JsonArray &() const {
   return _type == JSON_ARRAY ? *_content.asArray : JsonArray::invalid();
 }
 
-JsonObject &JsonValue::asObject() {
+JsonValue::operator JsonObject &() const {
   return _type == JSON_OBJECT ? *_content.asObject : JsonObject::invalid();
 }
 
-bool JsonValue::asBool() const {
+JsonValue::operator bool() const {
   return _type == JSON_BOOLEAN ? _content.asBoolean : false;
 }
 
-const char *JsonValue::asString() const {
+JsonValue::operator const char *() const {
   return _type == JSON_STRING ? _content.asString : NULL;
 }
 
-double JsonValue::asDouble() const {
+JsonValue::operator double() const {
   return _type >= JSON_DOUBLE_0_DECIMALS ? _content.asDouble : 0;
 }
 
-long JsonValue::asLong() const {
+JsonValue::operator long() const {
   return _type == JSON_LONG ? _content.asInteger : 0;
 }
 
@@ -98,4 +98,4 @@ void JsonValue::writeTo(JsonWriter &writer) const {
       writer.writeDouble(_content.asDouble, _type - JSON_DOUBLE_0_DECIMALS);
       break;
   }
-}
\ No newline at end of file
+}
diff --git a/test/JsonArray_Container_Tests.cpp b/test/JsonArray_Container_Tests.cpp
index a6b25802..7d0e5530 100644
--- a/test/JsonArray_Container_Tests.cpp
+++ b/test/JsonArray_Container_Tests.cpp
@@ -15,30 +15,43 @@ using namespace ArduinoJson;
 
 class JsonArray_Container_Tests : public ::testing::Test {
  protected:
-  JsonArray_Container_Tests()
-    : array(json.createArray()) {
+  JsonArray_Container_Tests() : array(json.createArray()) {}
+
+  template <typename T>
+  void firstMustEqual(T expected) {
+    itemMustEqual(0, expected);
   }
 
   template <typename T>
-  void firstElementMustBe(T expected) {
-    elementAtIndexMustBe(0, expected);
+  void secondMustEqual(T expected) {
+    itemMustEqual(1, expected);
   }
 
   template <typename T>
-  void secondElementMustBe(T expected) {
-    elementAtIndexMustBe(1, expected);
+  void firstMustReference(const T& expected) {
+    itemMustReference(0, expected);
+  }
+
+  template <typename T>
+  void secondMustReference(const T& expected) {
+    itemMustReference(1, expected);
   }
 
   void sizeMustBe(int expected) { EXPECT_EQ(expected, array.size()); }
 
   StaticJsonBuffer<256> json;
-  JsonArray &array;
+  JsonArray& array;
 
  private:
   template <typename T>
-  void elementAtIndexMustBe(int index, T expected) {
+  void itemMustEqual(int index, T expected) {
     EXPECT_EQ(expected, array[index].as<T>());
   }
+
+  template <typename T>
+  void itemMustReference(int index, const T& expected) {
+    EXPECT_EQ(&expected, &array[index].as<T&>());
+  }
 };
 
 TEST_F(JsonArray_Container_Tests, SuccessIsTrue) {
@@ -59,24 +72,24 @@ TEST_F(JsonArray_Container_Tests, CanStoreIntegers) {
   array.add(123);
   array.add(456);
 
-  firstElementMustBe(123);
-  secondElementMustBe(456);
+  firstMustEqual(123);
+  secondMustEqual(456);
 }
 
 TEST_F(JsonArray_Container_Tests, CanStoreDoubles) {
   array.add(123.45);
   array.add(456.78);
 
-  firstElementMustBe(123.45);
-  secondElementMustBe(456.78);
+  firstMustEqual(123.45);
+  secondMustEqual(456.78);
 }
 
 TEST_F(JsonArray_Container_Tests, CanStoreBooleans) {
   array.add(true);
   array.add(false);
 
-  firstElementMustBe(true);
-  secondElementMustBe(false);
+  firstMustEqual(true);
+  secondMustEqual(false);
 }
 
 TEST_F(JsonArray_Container_Tests, CanStoreStrings) {
@@ -86,44 +99,44 @@ TEST_F(JsonArray_Container_Tests, CanStoreStrings) {
   array.add(firstString);
   array.add(secondString);
 
-  firstElementMustBe(firstString);
-  secondElementMustBe(secondString);
+  firstMustEqual(firstString);
+  secondMustEqual(secondString);
 }
 
 TEST_F(JsonArray_Container_Tests, CanStoreNestedArrays) {
-  JsonArray &innerarray1 = json.createArray();
-  JsonArray &innerarray2 = json.createArray();
+  JsonArray& innerarray1 = json.createArray();
+  JsonArray& innerarray2 = json.createArray();
 
   array.add(innerarray1);
   array.add(innerarray2);
 
-  firstElementMustBe(innerarray1);
-  secondElementMustBe(innerarray2);
+  firstMustReference(innerarray1);
+  secondMustReference(innerarray2);
 }
 
 TEST_F(JsonArray_Container_Tests, CanStoreNestedObjects) {
-  JsonObject innerObject1 = json.createObject();
-  JsonObject innerObject2 = json.createObject();
+  JsonObject& innerObject1 = json.createObject();
+  JsonObject& innerObject2 = json.createObject();
 
   array.add(innerObject1);
   array.add(innerObject2);
 
-  firstElementMustBe(innerObject1);
-  secondElementMustBe(innerObject2);
+  firstMustReference(innerObject1);
+  secondMustReference(innerObject2);
 }
 
 TEST_F(JsonArray_Container_Tests, CanCreateNestedArrays) {
-  JsonArray innerarray1 = array.createNestedArray();
-  JsonArray innerarray2 = array.createNestedArray();
+  JsonArray& innerarray1 = array.createNestedArray();
+  JsonArray& innerarray2 = array.createNestedArray();
 
-  firstElementMustBe(innerarray1);
-  secondElementMustBe(innerarray2);
+  firstMustReference(innerarray1);
+  secondMustReference(innerarray2);
 }
 
 TEST_F(JsonArray_Container_Tests, CanCreateNestedObjects) {
-  JsonObject innerObject1 = array.createNestedObject();
-  JsonObject innerObject2 = array.createNestedObject();
+  JsonObject& innerObject1 = array.createNestedObject();
+  JsonObject& innerObject2 = array.createNestedObject();
 
-  firstElementMustBe(innerObject1);
-  secondElementMustBe(innerObject2);
+  firstMustReference(innerObject1);
+  secondMustReference(innerObject2);
 }
diff --git a/test/JsonArray_PrettyPrintTo_Tests.cpp b/test/JsonArray_PrettyPrintTo_Tests.cpp
index 7f9930be..b045bd42 100644
--- a/test/JsonArray_PrettyPrintTo_Tests.cpp
+++ b/test/JsonArray_PrettyPrintTo_Tests.cpp
@@ -13,13 +13,14 @@
 using namespace ArduinoJson;
 
 class JsonArray_PrettyPrintTo_Tests : public testing::Test {
+ public:
+  JsonArray_PrettyPrintTo_Tests() : array(json.createArray()) {}
+
  protected:
-  JsonArray array;
+  JsonArray& array;
   StaticJsonBuffer<30> json;
 
-  virtual void SetUp() { array = json.createArray(); }
-
-  void outputMustBe(const char *expected) {
+  void outputMustBe(const char* expected) {
     size_t n = array.prettyPrintTo(buffer, sizeof(buffer));
     EXPECT_STREQ(expected, buffer);
     EXPECT_EQ(strlen(expected), n);
@@ -63,11 +64,11 @@ TEST_F(JsonArray_PrettyPrintTo_Tests, EmptyNestedArrays) {
 }
 
 TEST_F(JsonArray_PrettyPrintTo_Tests, 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;
 
   outputMustBe(
diff --git a/test/JsonArray_PrintTo_Tests.cpp b/test/JsonArray_PrintTo_Tests.cpp
index 7a0974e7..2b197d1e 100644
--- a/test/JsonArray_PrintTo_Tests.cpp
+++ b/test/JsonArray_PrintTo_Tests.cpp
@@ -12,11 +12,12 @@
 using namespace ArduinoJson;
 
 class JsonArray_PrintTo_Tests : public testing::Test {
- protected:
-  JsonArray array;
-  StaticJsonBuffer<3> json;
+ public:
+  JsonArray_PrintTo_Tests() : array(json.createArray()) {}
 
-  virtual void SetUp() { array = json.createArray(); }
+ protected:
+  JsonArray &array;
+  StaticJsonBuffer<3> json;
 
   void outputMustBe(const char *expected) {
     size_t n = array.printTo(buffer, sizeof(buffer));
diff --git a/test/JsonObject_Container_Tests.cpp b/test/JsonObject_Container_Tests.cpp
index 399edbe1..62de2d1c 100644
--- a/test/JsonObject_Container_Tests.cpp
+++ b/test/JsonObject_Container_Tests.cpp
@@ -14,11 +14,12 @@
 using namespace ArduinoJson;
 
 class JsonObject_Container_Tests : public ::testing::Test {
- protected:
-  virtual void SetUp() { object = json.createObject(); }
+ public:
+  JsonObject_Container_Tests() : object(json.createObject()) {}
 
+ protected:
   StaticJsonBuffer<42> json;
-  JsonObject object;
+  JsonObject& object;
 };
 
 TEST_F(JsonObject_Container_Tests, InitialSizeIsZero) {
@@ -95,23 +96,23 @@ TEST_F(JsonObject_Container_Tests, CanStoreStrings) {
 }
 
 TEST_F(JsonObject_Container_Tests, CanStoreInnerArrays) {
-  JsonArray innerarray1 = json.createArray();
-  JsonArray innerarray2 = json.createArray();
+  JsonArray& innerarray1 = json.createArray();
+  JsonArray& innerarray2 = json.createArray();
 
   object["hello"] = innerarray1;
   object["world"] = innerarray2;
 
-  EXPECT_EQ(innerarray1, object["hello"].as<JsonArray>());
-  EXPECT_EQ(innerarray2, object["world"].as<JsonArray>());
+  EXPECT_EQ(&innerarray1, &object["hello"].asArray());
+  EXPECT_EQ(&innerarray2, &object["world"].asArray());
 }
 
 TEST_F(JsonObject_Container_Tests, CanStoreInnerObjects) {
-  JsonObject innerObject1 = json.createObject();
-  JsonObject innerObject2 = json.createObject();
+  JsonObject& innerObject1 = json.createObject();
+  JsonObject& innerObject2 = json.createObject();
 
   object["hello"] = innerObject1;
   object["world"] = innerObject2;
 
-  EXPECT_EQ(innerObject1, object["hello"].as<JsonObject>());
-  EXPECT_EQ(innerObject2, object["world"].as<JsonObject>());
+  EXPECT_EQ(&innerObject1, &object["hello"].asObject());
+  EXPECT_EQ(&innerObject2, &object["world"].asObject());
 }
diff --git a/test/JsonObject_Iterator_Tests.cpp b/test/JsonObject_Iterator_Tests.cpp
index 4df10990..02425980 100644
--- a/test/JsonObject_Iterator_Tests.cpp
+++ b/test/JsonObject_Iterator_Tests.cpp
@@ -13,7 +13,7 @@ using namespace ArduinoJson;
 TEST(JsonObject_Iterator_Test, SimpleTest) {
   StaticJsonBuffer<42> jsonBuffer;
 
-  JsonObject object = jsonBuffer.createObject();
+  JsonObject &object = jsonBuffer.createObject();
   object["ab"] = 12;
   object["cd"] = 34;
 
@@ -21,12 +21,12 @@ TEST(JsonObject_Iterator_Test, SimpleTest) {
   JsonObject::iterator end = object.end();
 
   EXPECT_NE(end, it);
-  EXPECT_STREQ("ab", it->key());
-  EXPECT_EQ(12, it->value().as<int>());
+  EXPECT_STREQ("ab", it->key);
+  EXPECT_EQ(12, it->value.as<int>());
   ++it;
   EXPECT_NE(end, it);
-  EXPECT_STREQ("cd", it->key());
-  EXPECT_EQ(34, it->value().as<int>());
+  EXPECT_STREQ("cd", it->key);
+  EXPECT_EQ(34, it->value.as<int>());
   ++it;
   EXPECT_EQ(object.end(), it);
 }