JsonVariant::add()
Description
When the JsonVariant points to an array, JsonVariant::add() appends a value to the array. Otherwise, this function does nothing.
In other words, JsonVariant::add() reproduces JsonArray::add().
Signatures
bool add(bool value) const;
bool add(float value) const;
bool add(double value) const;
bool add(signed char value) const;
bool add(signed long value) const;
bool add(signed int value) const;
bool add(signed short value) const;
bool add(unsigned char value) const;
bool add(unsigned long value) const;
bool add(unsigned int value) const;
bool add(unsigned short value) const;
bool add(char *value) const; // stores a copy
bool add(const char *value) const; // stores a pointer ⚠️
bool add(const __FlashStringHelper *value) const; // stores a copy
bool add(const String &value) const; // stores a copy
bool add(const std::string &value) const; // stores a copy
bool add(const Printable& value) const; // stores a copy
bool add(std::string_view value) const; // stores a copy
bool add(JsonArray array) const; // stores a deep copy
bool add(JsonObject object) const; // stores a deep copy
bool add(JsonVariant variant) const; // stores a deep copy
bool add(const JsonDocument& doc) const; // stores a deep copy
bool add(TEnum value) const; // alias of add(int)
bool add(T value) const; // calls user-defined function
Arguments
value: the value to append to the array.
All types are stored by copy, except const char* which is stored by pointer.
Return value
JsonVariant::add() returns a bool that tells whether the operation was successful or not:
trueif the value was successfully added.falseif there was not enough memory in theJsonDocument
User-defined types
JsonVariant::add() supports user-defined types by calling convertToJson().
For example, to support tm, you must define:
bool convertToJson(const tm& src, JsonVariant dst) {
char buf[32];
strftime(buf, sizeof(buf), "%FT%TZ", &src);
return dst.set(buf);
}
This feature was added in ArduinoJson 6.18.0, see article for details.
