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  • JavaScript 值删除对象(Object)的属性——delete

    原网址:https://blog.csdn.net/weixin_43553701/article/details/90757945

    删除对象属性的方法

    JS中如何删除对象中的某一属性

    1 var obj={
    2     name: 'zhagnsan',
    3     age: 19 
    4 }
    5 delete obj.name //true
    6 typeof obj.name //undefined

    通过delete操作符,可以实现兑现属性的删除操作,返回值是布尔。

    delete可以删除什么?

    1. 变量

    var name ='zs'  //已声明的变量
    delete name  //false
    console.log(typeof name)  //String
    
    age = 19  //未声明的变量
    delete age     //true
    typeof age //undefined
    
    this.val = 'fds'  //window下的变量
    delete this.val      //true
    console.log(typeof this.val)  //undefined

     已声明的变量在windows下可删除,未声明的变量不可删除。

    2.函数

    1 var fn = function(){}  //已声明的函数
    2 delete fn    //false
    3 console.log(typeof fn)  //function
    4 
    5 fn = function(){}  //未声明的函数
    6 delete fn    //true
    7 console.log(typeof fn)  //undefined

     3.数组

    var arr = ['1','2','3']  ///已声明的数组
    delete arr    //false
    console.log(typeof arr)  //object
    
    arr = ['1','2','3']  //未声明的数组
    delete arr   //true    
    console.log(typeof arr)   //undefined
    
    var arr = ['1','2','3']   //已声明的数组
    delete arr[1]  //true
    console.log(arr)   //['1','empty','3'] 

    4. 对象

     1 var person = {
     2   height: 180,
     3   long: 180,
     4   weight: 180,
     5   hobby: {
     6     ball: 'good',
     7     music: 'nice'
     8   }
     9 }
    10 delete person  ///false
    11 console.log(typeof person)   //object
    12 
    13 var person = {
    14   height: 180,
    15   long: 180,
    16   weight: 180,
    17   hobby: {
    18     ball: 'good',
    19     music: 'nice'
    20   }
    21 }
    22 delete person.hobby  ///true
    23 console.log(typeof person.hobby)  //undefined

     已声明的对象不可删除,对象中的对象属性可删除。

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  • 原文地址:https://www.cnblogs.com/luyj00436/p/15076312.html
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