ES5 常用 语法（object Arrary 函数绑定this指向）

时间：2022-05-08 20:39:14

ES object 扩展

ES object 扩展1.

<!DOCTYPE html>

<html>

<head>

  <link rel="shortcut icon" href="./assets/favicon.ico" />

  <meta charset="UTF-8">

  <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">

  <title>webpack</title>

</head>

<body>

  <script type="text/javascript">

//   ******object 扩展************
  //1.

  var obj={name:'kebo', sex:'男'}

  var obj1 =Object.create(obj,{

      age:{

          value:25,

          writable:true,//可被修改

          configurable:true, //可被删除

          enumerable:true

      }

  })

   console.log("obj1-----",obj1)

   obj1='kebo'  //    修改对象的属性

//    console.log("obj1-----###",obj1)

//    delete obj1  //    删除对象

//    console.log(obj1)

   for (var i in obj1){

        console.log(i)

   }

</script> 
</body>
</html>

　　ES object 扩展2.

<!DOCTYPE html>

<html>

<head>

  <link rel="shortcut icon" href="./assets/favicon.ico" />

  <meta charset="UTF-8">

  <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">

  <title>webpack</title>

</head>

<body>

  <script type="text/javascript">

//   ******object 扩展************

var obj2 ={fistName:'kebe',lastName:'bryant'};

Object.defineProperties(obj2,{

    fullName: {

        get: function(){ //   获取对应的值 惰性求值 被调用时才执行

            return this.fistName + ' ' + this.lastName;

        },

        set: function(data){ //   监听对象的属性 发送改变是调用

            console.log("obj2-------------",data)

            var names=data.split(' ')

            this.fistName=names[0]

            this.lastName=names[1]

            return this.fistName + ' ' + this.lastName;

        }

    },

})

console.log(obj2)

console.log('before',obj2.fullName)

obj2.fullName='kebe kebe';

console.log('after',obj2.fullName)

</script> 
</body> 
</html>

　　ES object 扩展3

<!DOCTYPE html>

<html>

<head>

  <link rel="shortcut icon" href="./assets/favicon.ico" />

  <meta charset="UTF-8">

  <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">

  <title>webpack</title>

</head>

<body>

  <script type="text/javascript">

//   ******object 扩展************

var obj3 ={

     fistName:'kebe',

     lastName:'bryant',

     get function(){ // 获取对应的值 惰性求值 被调用时才执行

         return this.fistName + ' ' + this.lastName;

      },

      set function(data){ // 监听对象的属性 发送改变是调用

          console.log("obj2-------------",data)

          var names=data.split(' ')

          this.fistName=names[0]

          this.lastName=names[1]

         return this.fistName + ' ' + this.lastName;

     }

}

console.log(obj2)

console.log('before',obj2.fullName)

obj2.fullName='kebe kebe';

console.log('after',obj2.fullName)

</script>

</body>

</html>

　　ES Arrary map, forEach ,filter(返回条件为true 的值)

var arr=[1,5,9,4,465,485,56,25,4,48,54]

console.log('4的下标',arr.indexOf(4))

console.log('4的下标',arr.lastIndexOf(4))

arr.forEach(function(item,index){

    console.log("item--",item)

})

var arr1=arr.map((item,index)=>{

    return item+10;

})

console.log("arr1--",arr1)

var arr2=arr.filter((item,index)=>{

    return item >25;

})

console.log("arr2 大于25的数--",arr2)

　　ES 函数语法 this指向绑定

var obj1={userName:'kobe'}

function foo1(data) {

    console.log(this,data) 

}

foo.call(obj1,33)  //直接从第二个数据开始穿入

foo.apply(obj1,[33,45]) //第二个参数必须是数组

var bar = foo.bind(obj) //绑定后没有以及执行 返回一个值

console.log('bar',bar)

bar()

console.log('2222222222')

foo.bind(obj)(33666) //加（）调用函数  直接从第二个数据开始穿入

var obj1={userName:'kobe'}

setTimeout(function () {

    console.log("this---",this)

}.bind(obj1),1000)

　　

　　

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