flutter_parse_json_basic.dart

import 'dart:convert';

// article - How to parde Json in Flutter
// https://www.filledstacks.com/snippet/how-to-parse-json-in-flutter/

void main() {
  var jsonData = '{"name" : "Dane", "alias" : "FilledStacks"}';
  print(jsonData);

  var parsedJson = json.decode(jsonData);
  print(parsedJson);
  print('${parsedJson.runtimeType} : $parsedJson');

  // Direct Parsing and Usage
  var name = parsedJson['name'];
  var alias = parsedJson['alias'];
  print('$name is $alias');

  // Parse Into Object
  // Instead of using the parsed data directly it's common practice under
  // programmers to put this data into a class that models your data for you.
  // This is commonly done through a named constructor in Dart. Let's put our test
  // data into a model. We'll define the model in the basic way first, then get to
  // the named constructor.

  // var user = User(parsedJson);
  // print('${user.name} is ${user.alias}');

  var user = User.fromJson(parsedJson);
  print('${user.name} is ${user.alias}');
}

//class User {
//  String name;
//  String alias;

//  User(Map<String, dynamic> data) {
//    name = data['name'];
//    alias = data['alias'];
//  }
//}

// The above way would be fine, but having only that one constructor limits you and does not
// leave your model open for extension. You'll have to modify it to get any other functionality
// into it. Instead the common practice is to have a constructor that sets all the properties
// for you and use a named constructor to create a model explicitly using outside data.
// https://javiercbk.github.io/json_to_dart/

class User {
  String name;
  String alias;

  User(Map<String, dynamic> data) {
    name = data['name'];
    alias = data['alias'];
  }
  
  // named constructor
  User.fromJson(Map<String, dynamic> data) 
      : name = data['name'],
        alias = data['alias'];
}