From c6c0649d70f854f258f908ec4c1a7cb013c18e31 Mon Sep 17 00:00:00 2001
From: Benoit Blanchon <git@benoitblanchon.fr>
Date: Wed, 23 Oct 2024 15:54:08 +0200
Subject: [PATCH] Replace `typedef` with `using`

---
 extras/tests/JsonDocument/ElementProxy.cpp                | 2 +-
 extras/tests/JsonDocument/MemberProxy.cpp                 | 4 ++--
 extras/tests/JsonVariant/stl_containers.cpp               | 2 +-
 extras/tests/Misc/custom_string.hpp                       | 2 +-
 src/ArduinoJson/Array/JsonArray.hpp                       | 2 +-
 src/ArduinoJson/Array/JsonArrayConst.hpp                  | 2 +-
 src/ArduinoJson/Json/PrettyJsonSerializer.hpp             | 2 +-
 src/ArduinoJson/Json/TextFormatter.hpp                    | 2 +-
 src/ArduinoJson/Numbers/FloatParts.hpp                    | 2 +-
 src/ArduinoJson/Numbers/FloatTraits.hpp                   | 8 ++++----
 src/ArduinoJson/Numbers/JsonFloat.hpp                     | 4 ++--
 src/ArduinoJson/Numbers/JsonInteger.hpp                   | 8 ++++----
 src/ArduinoJson/Numbers/parseNumber.hpp                   | 6 +++---
 src/ArduinoJson/Object/JsonObject.hpp                     | 2 +-
 src/ArduinoJson/Object/JsonObjectConst.hpp                | 2 +-
 src/ArduinoJson/Polyfills/integer.hpp                     | 6 +++---
 src/ArduinoJson/Polyfills/type_traits/conditional.hpp     | 4 ++--
 src/ArduinoJson/Polyfills/type_traits/enable_if.hpp       | 2 +-
 src/ArduinoJson/Polyfills/type_traits/remove_const.hpp    | 4 ++--
 src/ArduinoJson/Polyfills/type_traits/remove_cv.hpp       | 8 ++++----
 .../Polyfills/type_traits/remove_reference.hpp            | 4 ++--
 src/ArduinoJson/Polyfills/type_traits/type_identity.hpp   | 2 +-
 src/ArduinoJson/Strings/Adapters/FlashString.hpp          | 4 ++--
 src/ArduinoJson/Strings/Adapters/JsonString.hpp           | 2 +-
 src/ArduinoJson/Strings/Adapters/RamString.hpp            | 8 ++++----
 src/ArduinoJson/Strings/Adapters/StringObject.hpp         | 2 +-
 src/ArduinoJson/Variant/JsonVariantCopier.hpp             | 2 +-
 src/ArduinoJson/Variant/JsonVariantVisitor.hpp            | 2 +-
 src/ArduinoJson/Variant/VariantDataVisitor.hpp            | 2 +-
 src/ArduinoJson/Variant/VariantTo.hpp                     | 6 +++---
 30 files changed, 54 insertions(+), 54 deletions(-)

diff --git a/extras/tests/JsonDocument/ElementProxy.cpp b/extras/tests/JsonDocument/ElementProxy.cpp
index 0a9039d4..693c3d5d 100644
--- a/extras/tests/JsonDocument/ElementProxy.cpp
+++ b/extras/tests/JsonDocument/ElementProxy.cpp
@@ -7,7 +7,7 @@
 
 #include "Literals.hpp"
 
-typedef ArduinoJson::detail::ElementProxy<JsonDocument&> ElementProxy;
+using ElementProxy = ArduinoJson::detail::ElementProxy<JsonDocument&>;
 
 TEST_CASE("ElementProxy::add()") {
   JsonDocument doc;
diff --git a/extras/tests/JsonDocument/MemberProxy.cpp b/extras/tests/JsonDocument/MemberProxy.cpp
index b48eda1f..fa672cf3 100644
--- a/extras/tests/JsonDocument/MemberProxy.cpp
+++ b/extras/tests/JsonDocument/MemberProxy.cpp
@@ -14,8 +14,8 @@
 using ArduinoJson::detail::sizeofArray;
 using ArduinoJson::detail::sizeofObject;
 
-typedef ArduinoJson::detail::MemberProxy<JsonDocument&, const char*>
-    MemberProxy;
+using MemberProxy =
+    ArduinoJson::detail::MemberProxy<JsonDocument&, const char*>;
 
 TEST_CASE("MemberProxy::add()") {
   JsonDocument doc;
diff --git a/extras/tests/JsonVariant/stl_containers.cpp b/extras/tests/JsonVariant/stl_containers.cpp
index 05d10209..6ffa5808 100644
--- a/extras/tests/JsonVariant/stl_containers.cpp
+++ b/extras/tests/JsonVariant/stl_containers.cpp
@@ -99,7 +99,7 @@ TEST_CASE("vector<int>") {
 }
 
 TEST_CASE("array<int, 2>") {
-  typedef std::array<int, 2> array_type;
+  using array_type = std::array<int, 2>;
 
   SECTION("toJson") {
     array_type v;
diff --git a/extras/tests/Misc/custom_string.hpp b/extras/tests/Misc/custom_string.hpp
index acc67521..9be1f547 100644
--- a/extras/tests/Misc/custom_string.hpp
+++ b/extras/tests/Misc/custom_string.hpp
@@ -8,4 +8,4 @@
 
 struct custom_char_traits : std::char_traits<char> {};
 
-typedef std::basic_string<char, custom_char_traits> custom_string;
+using custom_string = std::basic_string<char, custom_char_traits>;
diff --git a/src/ArduinoJson/Array/JsonArray.hpp b/src/ArduinoJson/Array/JsonArray.hpp
index 9a4e5f97..0e3ea2ee 100644
--- a/src/ArduinoJson/Array/JsonArray.hpp
+++ b/src/ArduinoJson/Array/JsonArray.hpp
@@ -17,7 +17,7 @@ class JsonArray : public detail::VariantOperators<JsonArray> {
   friend class detail::VariantAttorney;
 
  public:
-  typedef JsonArrayIterator iterator;
+  using iterator = JsonArrayIterator;
 
   // Constructs an unbound reference.
   JsonArray() : data_(0), resources_(0) {}
diff --git a/src/ArduinoJson/Array/JsonArrayConst.hpp b/src/ArduinoJson/Array/JsonArrayConst.hpp
index c6e027f8..6b9db192 100644
--- a/src/ArduinoJson/Array/JsonArrayConst.hpp
+++ b/src/ArduinoJson/Array/JsonArrayConst.hpp
@@ -19,7 +19,7 @@ class JsonArrayConst : public detail::VariantOperators<JsonArrayConst> {
   friend class detail::VariantAttorney;
 
  public:
-  typedef JsonArrayConstIterator iterator;
+  using iterator = JsonArrayConstIterator;
 
   // Returns an iterator to the first element of the array.
   // https://arduinojson.org/v7/api/jsonarrayconst/begin/
diff --git a/src/ArduinoJson/Json/PrettyJsonSerializer.hpp b/src/ArduinoJson/Json/PrettyJsonSerializer.hpp
index 9ae03673..56cedf2e 100644
--- a/src/ArduinoJson/Json/PrettyJsonSerializer.hpp
+++ b/src/ArduinoJson/Json/PrettyJsonSerializer.hpp
@@ -13,7 +13,7 @@ ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
 template <typename TWriter>
 class PrettyJsonSerializer : public JsonSerializer<TWriter> {
-  typedef JsonSerializer<TWriter> base;
+  using base = JsonSerializer<TWriter>;
 
  public:
   PrettyJsonSerializer(TWriter writer, const ResourceManager* resources)
diff --git a/src/ArduinoJson/Json/TextFormatter.hpp b/src/ArduinoJson/Json/TextFormatter.hpp
index 5b94b5ed..0fab3966 100644
--- a/src/ArduinoJson/Json/TextFormatter.hpp
+++ b/src/ArduinoJson/Json/TextFormatter.hpp
@@ -105,7 +105,7 @@ class TextFormatter {
 
   template <typename T>
   enable_if_t<is_signed<T>::value> writeInteger(T value) {
-    typedef make_unsigned_t<T> unsigned_type;
+    using unsigned_type = make_unsigned_t<T>;
     unsigned_type unsigned_value;
     if (value < 0) {
       writeRaw('-');
diff --git a/src/ArduinoJson/Numbers/FloatParts.hpp b/src/ArduinoJson/Numbers/FloatParts.hpp
index 0affe062..536ae2a1 100644
--- a/src/ArduinoJson/Numbers/FloatParts.hpp
+++ b/src/ArduinoJson/Numbers/FloatParts.hpp
@@ -20,7 +20,7 @@ struct FloatParts {
 
 template <typename TFloat>
 inline int16_t normalize(TFloat& value) {
-  typedef FloatTraits<TFloat> traits;
+  using traits = FloatTraits<TFloat>;
   int16_t powersOf10 = 0;
 
   int8_t index = sizeof(TFloat) == 8 ? 8 : 5;
diff --git a/src/ArduinoJson/Numbers/FloatTraits.hpp b/src/ArduinoJson/Numbers/FloatTraits.hpp
index 2dcbe10c..ea996259 100644
--- a/src/ArduinoJson/Numbers/FloatTraits.hpp
+++ b/src/ArduinoJson/Numbers/FloatTraits.hpp
@@ -21,12 +21,12 @@ struct FloatTraits {};
 
 template <typename T>
 struct FloatTraits<T, 8 /*64bits*/> {
-  typedef uint64_t mantissa_type;
+  using mantissa_type = uint64_t;
   static const short mantissa_bits = 52;
   static const mantissa_type mantissa_max =
       (mantissa_type(1) << mantissa_bits) - 1;
 
-  typedef int16_t exponent_type;
+  using exponent_type = int16_t;
   static const exponent_type exponent_max = 308;
 
   static pgm_ptr<T> positiveBinaryPowersOfTen() {
@@ -105,12 +105,12 @@ struct FloatTraits<T, 8 /*64bits*/> {
 
 template <typename T>
 struct FloatTraits<T, 4 /*32bits*/> {
-  typedef uint32_t mantissa_type;
+  using mantissa_type = uint32_t;
   static const short mantissa_bits = 23;
   static const mantissa_type mantissa_max =
       (mantissa_type(1) << mantissa_bits) - 1;
 
-  typedef int8_t exponent_type;
+  using exponent_type = int8_t;
   static const exponent_type exponent_max = 38;
 
   static pgm_ptr<T> positiveBinaryPowersOfTen() {
diff --git a/src/ArduinoJson/Numbers/JsonFloat.hpp b/src/ArduinoJson/Numbers/JsonFloat.hpp
index 89f3351b..e370f66f 100644
--- a/src/ArduinoJson/Numbers/JsonFloat.hpp
+++ b/src/ArduinoJson/Numbers/JsonFloat.hpp
@@ -10,9 +10,9 @@
 ARDUINOJSON_BEGIN_PUBLIC_NAMESPACE
 
 #if ARDUINOJSON_USE_DOUBLE
-typedef double JsonFloat;
+using JsonFloat = double;
 #else
-typedef float JsonFloat;
+using JsonFloat = float;
 #endif
 
 ARDUINOJSON_END_PUBLIC_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/JsonInteger.hpp b/src/ArduinoJson/Numbers/JsonInteger.hpp
index ae025b72..d65805c1 100644
--- a/src/ArduinoJson/Numbers/JsonInteger.hpp
+++ b/src/ArduinoJson/Numbers/JsonInteger.hpp
@@ -12,11 +12,11 @@
 ARDUINOJSON_BEGIN_PUBLIC_NAMESPACE
 
 #if ARDUINOJSON_USE_LONG_LONG
-typedef int64_t JsonInteger;
-typedef uint64_t JsonUInt;
+using JsonInteger = int64_t;
+using JsonUInt = uint64_t;
 #else
-typedef long JsonInteger;
-typedef unsigned long JsonUInt;
+using JsonInteger = long;
+using JsonUInt = unsigned long;
 #endif
 
 ARDUINOJSON_END_PUBLIC_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/parseNumber.hpp b/src/ArduinoJson/Numbers/parseNumber.hpp
index 2df8cdc8..7f4b2206 100644
--- a/src/ArduinoJson/Numbers/parseNumber.hpp
+++ b/src/ArduinoJson/Numbers/parseNumber.hpp
@@ -103,9 +103,9 @@ class Number {
 };
 
 inline Number parseNumber(const char* s) {
-  typedef FloatTraits<JsonFloat> traits;
-  typedef largest_type<traits::mantissa_type, JsonUInt> mantissa_t;
-  typedef traits::exponent_type exponent_t;
+  using traits = FloatTraits<JsonFloat>;
+  using mantissa_t = largest_type<traits::mantissa_type, JsonUInt>;
+  using exponent_t = traits::exponent_type;
 
   ARDUINOJSON_ASSERT(s != 0);
 
diff --git a/src/ArduinoJson/Object/JsonObject.hpp b/src/ArduinoJson/Object/JsonObject.hpp
index 2eeeed36..d9693f73 100644
--- a/src/ArduinoJson/Object/JsonObject.hpp
+++ b/src/ArduinoJson/Object/JsonObject.hpp
@@ -17,7 +17,7 @@ class JsonObject : public detail::VariantOperators<JsonObject> {
   friend class detail::VariantAttorney;
 
  public:
-  typedef JsonObjectIterator iterator;
+  using iterator = JsonObjectIterator;
 
   // Creates an unbound reference.
   JsonObject() : data_(0), resources_(0) {}
diff --git a/src/ArduinoJson/Object/JsonObjectConst.hpp b/src/ArduinoJson/Object/JsonObjectConst.hpp
index 3af7d12e..9b2effbd 100644
--- a/src/ArduinoJson/Object/JsonObjectConst.hpp
+++ b/src/ArduinoJson/Object/JsonObjectConst.hpp
@@ -16,7 +16,7 @@ class JsonObjectConst : public detail::VariantOperators<JsonObjectConst> {
   friend class detail::VariantAttorney;
 
  public:
-  typedef JsonObjectConstIterator iterator;
+  using iterator = JsonObjectConstIterator;
 
   // Creates an unbound reference.
   JsonObjectConst() : data_(0), resources_(0) {}
diff --git a/src/ArduinoJson/Polyfills/integer.hpp b/src/ArduinoJson/Polyfills/integer.hpp
index 8b74bd9a..c56e1e93 100644
--- a/src/ArduinoJson/Polyfills/integer.hpp
+++ b/src/ArduinoJson/Polyfills/integer.hpp
@@ -15,17 +15,17 @@ struct uint_;
 
 template <>
 struct uint_<8> {
-  typedef uint8_t type;
+  using type = uint8_t;
 };
 
 template <>
 struct uint_<16> {
-  typedef uint16_t type;
+  using type = uint16_t;
 };
 
 template <>
 struct uint_<32> {
-  typedef uint32_t type;
+  using type = uint32_t;
 };
 
 template <int Bits>
diff --git a/src/ArduinoJson/Polyfills/type_traits/conditional.hpp b/src/ArduinoJson/Polyfills/type_traits/conditional.hpp
index bebd844a..75ebdd48 100644
--- a/src/ArduinoJson/Polyfills/type_traits/conditional.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/conditional.hpp
@@ -10,12 +10,12 @@ ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
 template <bool Condition, class TrueType, class FalseType>
 struct conditional {
-  typedef TrueType type;
+  using type = TrueType;
 };
 
 template <class TrueType, class FalseType>
 struct conditional<false, TrueType, FalseType> {
-  typedef FalseType type;
+  using type = FalseType;
 };
 
 template <bool Condition, class TrueType, class FalseType>
diff --git a/src/ArduinoJson/Polyfills/type_traits/enable_if.hpp b/src/ArduinoJson/Polyfills/type_traits/enable_if.hpp
index 0fed8f4e..f1184f2b 100644
--- a/src/ArduinoJson/Polyfills/type_traits/enable_if.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/enable_if.hpp
@@ -14,7 +14,7 @@ struct enable_if {};
 
 template <typename T>
 struct enable_if<true, T> {
-  typedef T type;
+  using type = T;
 };
 
 template <bool Condition, typename T = void>
diff --git a/src/ArduinoJson/Polyfills/type_traits/remove_const.hpp b/src/ArduinoJson/Polyfills/type_traits/remove_const.hpp
index 5e08dce8..22406e5b 100644
--- a/src/ArduinoJson/Polyfills/type_traits/remove_const.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/remove_const.hpp
@@ -11,11 +11,11 @@ ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 // A meta-function that return the type T without the const modifier
 template <typename T>
 struct remove_const {
-  typedef T type;
+  using type = T;
 };
 template <typename T>
 struct remove_const<const T> {
-  typedef T type;
+  using type = T;
 };
 
 template <typename T>
diff --git a/src/ArduinoJson/Polyfills/type_traits/remove_cv.hpp b/src/ArduinoJson/Polyfills/type_traits/remove_cv.hpp
index 0c7b633e..67d75c69 100644
--- a/src/ArduinoJson/Polyfills/type_traits/remove_cv.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/remove_cv.hpp
@@ -10,19 +10,19 @@ ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
 template <typename T>
 struct remove_cv {
-  typedef T type;
+  using type = T;
 };
 template <typename T>
 struct remove_cv<const T> {
-  typedef T type;
+  using type = T;
 };
 template <typename T>
 struct remove_cv<volatile T> {
-  typedef T type;
+  using type = T;
 };
 template <typename T>
 struct remove_cv<const volatile T> {
-  typedef T type;
+  using type = T;
 };
 
 template <typename T>
diff --git a/src/ArduinoJson/Polyfills/type_traits/remove_reference.hpp b/src/ArduinoJson/Polyfills/type_traits/remove_reference.hpp
index c5ddeed6..60e31b0d 100644
--- a/src/ArduinoJson/Polyfills/type_traits/remove_reference.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/remove_reference.hpp
@@ -11,11 +11,11 @@ ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 // A meta-function that return the type T without the reference modifier.
 template <typename T>
 struct remove_reference {
-  typedef T type;
+  using type = T;
 };
 template <typename T>
 struct remove_reference<T&> {
-  typedef T type;
+  using type = T;
 };
 
 template <typename T>
diff --git a/src/ArduinoJson/Polyfills/type_traits/type_identity.hpp b/src/ArduinoJson/Polyfills/type_traits/type_identity.hpp
index 0dd1a9f9..ea899f65 100644
--- a/src/ArduinoJson/Polyfills/type_traits/type_identity.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/type_identity.hpp
@@ -10,7 +10,7 @@ ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
 template <typename T>
 struct type_identity {
-  typedef T type;
+  using type = T;
 };
 
 ARDUINOJSON_END_PRIVATE_NAMESPACE
diff --git a/src/ArduinoJson/Strings/Adapters/FlashString.hpp b/src/ArduinoJson/Strings/Adapters/FlashString.hpp
index fafed963..4cbbc0f4 100644
--- a/src/ArduinoJson/Strings/Adapters/FlashString.hpp
+++ b/src/ArduinoJson/Strings/Adapters/FlashString.hpp
@@ -74,7 +74,7 @@ class FlashString {
 
 template <>
 struct StringAdapter<const __FlashStringHelper*, void> {
-  typedef FlashString AdaptedString;
+  using AdaptedString = FlashString;
 
   static AdaptedString adapt(const __FlashStringHelper* s) {
     return AdaptedString(s, s ? strlen_P(reinterpret_cast<const char*>(s)) : 0);
@@ -83,7 +83,7 @@ struct StringAdapter<const __FlashStringHelper*, void> {
 
 template <>
 struct SizedStringAdapter<const __FlashStringHelper*, void> {
-  typedef FlashString AdaptedString;
+  using AdaptedString = FlashString;
 
   static AdaptedString adapt(const __FlashStringHelper* s, size_t n) {
     return AdaptedString(s, n);
diff --git a/src/ArduinoJson/Strings/Adapters/JsonString.hpp b/src/ArduinoJson/Strings/Adapters/JsonString.hpp
index b98c4078..b611bcf8 100644
--- a/src/ArduinoJson/Strings/Adapters/JsonString.hpp
+++ b/src/ArduinoJson/Strings/Adapters/JsonString.hpp
@@ -25,7 +25,7 @@ class JsonStringAdapter : public SizedRamString {
 
 template <>
 struct StringAdapter<JsonString> {
-  typedef JsonStringAdapter AdaptedString;
+  using AdaptedString = JsonStringAdapter;
 
   static AdaptedString adapt(const JsonString& s) {
     return AdaptedString(s);
diff --git a/src/ArduinoJson/Strings/Adapters/RamString.hpp b/src/ArduinoJson/Strings/Adapters/RamString.hpp
index c27c4b3d..3a327a2a 100644
--- a/src/ArduinoJson/Strings/Adapters/RamString.hpp
+++ b/src/ArduinoJson/Strings/Adapters/RamString.hpp
@@ -63,7 +63,7 @@ class ZeroTerminatedRamString {
 
 template <typename TChar>
 struct StringAdapter<TChar*, enable_if_t<IsChar<TChar>::value>> {
-  typedef ZeroTerminatedRamString AdaptedString;
+  using AdaptedString = ZeroTerminatedRamString;
 
   static AdaptedString adapt(const TChar* p) {
     return AdaptedString(reinterpret_cast<const char*>(p));
@@ -72,7 +72,7 @@ struct StringAdapter<TChar*, enable_if_t<IsChar<TChar>::value>> {
 
 template <typename TChar, size_t N>
 struct StringAdapter<TChar[N], enable_if_t<IsChar<TChar>::value>> {
-  typedef ZeroTerminatedRamString AdaptedString;
+  using AdaptedString = ZeroTerminatedRamString;
 
   static AdaptedString adapt(const TChar* p) {
     return AdaptedString(reinterpret_cast<const char*>(p));
@@ -90,7 +90,7 @@ class StaticStringAdapter : public ZeroTerminatedRamString {
 
 template <>
 struct StringAdapter<const char*, void> {
-  typedef StaticStringAdapter AdaptedString;
+  using AdaptedString = StaticStringAdapter;
 
   static AdaptedString adapt(const char* p) {
     return AdaptedString(p);
@@ -132,7 +132,7 @@ class SizedRamString {
 
 template <typename TChar>
 struct SizedStringAdapter<TChar*, enable_if_t<IsChar<TChar>::value>> {
-  typedef SizedRamString AdaptedString;
+  using AdaptedString = SizedRamString;
 
   static AdaptedString adapt(const TChar* p, size_t n) {
     return AdaptedString(reinterpret_cast<const char*>(p), n);
diff --git a/src/ArduinoJson/Strings/Adapters/StringObject.hpp b/src/ArduinoJson/Strings/Adapters/StringObject.hpp
index 095f40dc..d29d6537 100644
--- a/src/ArduinoJson/Strings/Adapters/StringObject.hpp
+++ b/src/ArduinoJson/Strings/Adapters/StringObject.hpp
@@ -15,7 +15,7 @@ struct StringAdapter<
     T,
     enable_if_t<(string_traits<T>::has_cstr || string_traits<T>::has_data) &&
                 (string_traits<T>::has_length || string_traits<T>::has_size)>> {
-  typedef SizedRamString AdaptedString;
+  using AdaptedString = SizedRamString;
 
   static AdaptedString adapt(const T& s) {
     return AdaptedString(get_data(s), get_size(s));
diff --git a/src/ArduinoJson/Variant/JsonVariantCopier.hpp b/src/ArduinoJson/Variant/JsonVariantCopier.hpp
index 032f1f84..659069dc 100644
--- a/src/ArduinoJson/Variant/JsonVariantCopier.hpp
+++ b/src/ArduinoJson/Variant/JsonVariantCopier.hpp
@@ -11,7 +11,7 @@ ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
 class JsonVariantCopier {
  public:
-  typedef bool result_type;
+  using result_type = bool;
 
   JsonVariantCopier(JsonVariant dst) : dst_(dst) {}
 
diff --git a/src/ArduinoJson/Variant/JsonVariantVisitor.hpp b/src/ArduinoJson/Variant/JsonVariantVisitor.hpp
index 83f51539..6069b6e6 100644
--- a/src/ArduinoJson/Variant/JsonVariantVisitor.hpp
+++ b/src/ArduinoJson/Variant/JsonVariantVisitor.hpp
@@ -13,7 +13,7 @@ ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
 template <typename TResult>
 struct JsonVariantVisitor {
-  typedef TResult result_type;
+  using result_type = TResult;
 
   template <typename T>
   TResult visit(const T&) {
diff --git a/src/ArduinoJson/Variant/VariantDataVisitor.hpp b/src/ArduinoJson/Variant/VariantDataVisitor.hpp
index 631bce7c..662ab13c 100644
--- a/src/ArduinoJson/Variant/VariantDataVisitor.hpp
+++ b/src/ArduinoJson/Variant/VariantDataVisitor.hpp
@@ -13,7 +13,7 @@ ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
 template <typename TResult>
 struct VariantDataVisitor {
-  typedef TResult result_type;
+  using result_type = TResult;
 
   template <typename T>
   TResult visit(const T&) {
diff --git a/src/ArduinoJson/Variant/VariantTo.hpp b/src/ArduinoJson/Variant/VariantTo.hpp
index c533040d..f159aef2 100644
--- a/src/ArduinoJson/Variant/VariantTo.hpp
+++ b/src/ArduinoJson/Variant/VariantTo.hpp
@@ -20,15 +20,15 @@ struct VariantTo {};
 
 template <>
 struct VariantTo<JsonArray> {
-  typedef JsonArray type;
+  using type = JsonArray;
 };
 template <>
 struct VariantTo<JsonObject> {
-  typedef JsonObject type;
+  using type = JsonObject;
 };
 template <>
 struct VariantTo<JsonVariant> {
-  typedef JsonVariant type;
+  using type = JsonVariant;
 };
 
 ARDUINOJSON_END_PRIVATE_NAMESPACE