text: //Array.from
  //可以将部署了Iterator接口的对象，类数组的对象（该对象必须要有length属性）转换成数组
  
  console.log('-----step1，转换map')
  const map1 = new Map();
  map1.set('k1', 1);
  map1.set('k2', 2);
  map1.set('k3', 3);
  console.log('%s', Array.from(map1))
  
  console.log('-----step2，转换set')
  const set1 = new Set();
  set1.add(1).add(2).add(3)
  console.log('%s', Array.from(set1))
  
  console.log('-----step3，转换字符串')
  console.log('%s', Array.from('hello world'))
  console.log('%s', Array.from('\u767d\u8272\u7684\u6d77'))
  
  console.log('-----step4，类数组对象')
  
  console.log('%s', Array.from({
    0: '0',
    1: '1',
    3: '3',
    length:4
  }))
  
  console.log('%s', Array.from({
    0: 0,
    1: 1
  }))
  
  console.log('%s', Array.from({
    a: '1',
    b: '2',
    length:2
  }))
  
  console.log('-----step5，第二个参数作用')
  
  console.log('%s', Array.from([1, 2, 3, 4, 5], (n) => n + 1))
  
  
  console.log('-----step6，第三个参数作用，绑定this')
  
  let diObj = {
    handle: function(n){
      return n + 2
    }
  }
  console.log('%s', Array.from(
    [1, 2, 3, 4, 5], 
    function (x){
      return this.handle(x)
    }, 
    diObj))