CAUTION: SLIPPERY FLOORThe Arduino Library Manager installs the ArduinoJson version 6 by default.
However, using version 5 is highly recommended because version 6 is still in beta stage.
Open the Arduino Library Manager and make sure that ArduinoJson version 5 is installed.
Returns the number of key/value pairs in the object.
size_t size() const;
An unsigned integer containing the number of key/value pairs in the object.
JsonObject& object = jsonBuffer.createObject(); object["hello"] = "world"; Serial.println(object.size()); // 1