safemap 2.0.0-nullsafety.0

Safely get value with Type from JSON map. Will return null value when value was wrong.

example/lib/main.dart

import 'package:flutter/material.dart';
import 'package:safemap/safemap.dart';
void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    // source map
    Map map = {
      'id': 3,
      'tag': 'student',
      'info': {
        'name': 'Jerry',
      },
      'class': [
        {
          "name": 'class 1',
          'tag': '',
        },
        {},
      ],
    };
    SafeMap safeMap = SafeMap(map);

    // 取值,错误的类型会返回SafeMap(null)
    assert(safeMap['id'].value == 3);
    assert(safeMap['id'].string == null);

    // 错误的下标也会返回SafeMap(null)
    assert(safeMap['tag'].value == 'student');
    assert(safeMap['tag12345'].value == null);

    // 连续取值,可以一直安全取值,只会返回SafeMap(null).
    assert(safeMap['info']['name'].value == 'Jerry');
    assert(safeMap['a']['b']['b']['b']['b']['b'].value == null);

    // 取出数组，也可以通过数组下标继续取值
    assert(safeMap['class'].list.length == 2);
    assert(safeMap['class'][0]['name'].value == 'class 1');

    // {},[],0,'',null 都会被判断为空
    assert(safeMap['class'][0]['tag'].isEmpty());
    assert(safeMap['class'][1].isEmpty());

    // 越界也会返回SafeMap(null)，判断isEmpty为true
    assert(safeMap['class'][2].isEmpty());

    
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: '断言结束，运行正常'),
    );
  }
}

class MyHomePage extends StatelessWidget {
  final String title;

  const MyHomePage({Key key, this.title}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text(title),
      ),
    );
  }
}