API Reference
JsonObject::size()
CAUTION: SLIPPERY FLOOR
The 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.
Description
Returns the number of key/value pairs in the object.
Signature
size_t size() const;
Return value
An unsigned integer containing the number of key/value pairs in the object.
Example
JsonObject& object = jsonBuffer.createObject();
object["hello"] = "world";
Serial.println(object.size()); // 1