main.dart

import 'dart:convert';

void main() {
  // sample JSON
  String _userJsonInitial = '''{
        "name" : "Mock",
         "age" : 20,
         "subscribed" : true}''';

  // Define the function that will return the future
  Future<Map<String, dynamic>> myJsonFutureFunction() async {
    Map<String, dynamic> myDecodedJson = await json.decode(_userJsonInitial);
    print(myDecodedJson);
    return myDecodedJson;
  }
  
  // Now run it
  myJsonFutureFunction();
}