javascript - 使用动态键创建对象[重复](Creating object with dynamic keys [duplicate])

Question

(This question already has answers here) : ((这个问题已经在这里有了答案) ：)

How to use a variable for a key in a JavaScript object literal? (如何在JavaScript对象文字中使用变量作为键？) (12 answers) (（12个答案）)

Closed 5 years ago . (5年前关闭。)

First off, I'm using Cheerio for some DOM access and parsing with Node.js.(首先，我使用Cheerio进行一些DOM访问，并使用Node.js进行解析。)

Good times.(美好的时光。)

Heres the situation:(情况如下：)

I have a function that I need to create an object.(我具有创建对象所需的功能。)

That object uses variables for both its keys and values, and then return that single object.(该对象为其键和值使用变量，然后返回该单个对象。) Example:(例：)

stuff = function (thing, callback) {
  var inputs  = $('div.quantity > input').map(function(){
    var key   = this.attr('name')
     ,  value = this.attr('value');

     return { key : value }
  }) 

  callback(null, inputs);
}

It outputs this:(它输出：)

[ { key: '1' }, { key: '1' } ]

( .map() returns an array of objects fyi)(（ .map()返回对象数组fyi）)

I need key to actually be the string from this.attr('name') .(我需要key实际上是this.attr('name')的字符串。)

Whats the best way to assign a string as a key in Javascript, considering what I'm trying to do?(考虑到我要做什么，在Java中将字符串分配为键的最佳方法是什么？)

  ask by JDillon522 translate from so

Answer 1

In the new ES2015 standard for JavaScript (formerly called ES6), objects can be created with computed keys : Object Initializer spec .(在JavaScript的新ES2015标准 （以前称为ES6）中，可以使用计算键创建对象 ： Object Initializer spec 。)

The syntax is:(语法为：)

var obj = {
  [myKey]: value,
}

If applied to the OP's scenario, it would turn into:(如果应用于OP的场景，它将变成：)

stuff = function (thing, callback) {
  var inputs  = $('div.quantity > input').map(function(){
    return {
      [this.attr('name')]: this.attr('value'),
    };
  }) 

  callback(null, inputs);
}

Note: A transpiler is still required for browser compatiblity .(注意： 浏览器兼容性仍然需要编译器 。)

Using Babel or Google's traceur , it is possible to use this syntax today .(使用Babel或Google的traceur ， 今天可以使用此语法 。)

---

In earlier JavaScript specifications (ES5 and below), the key in an object literal is always interpreted literally, as a string.(在早期的JavaScript规范（ES5及更低版本）中，对象文字中的键始终按字面意义解释为字符串。)

To use a "dynamic" key, you have to use bracket notation :(要使用“动态”键，必须使用方括号表示法 ：)

var obj = {};
obj[myKey] = value;

In your case:(在您的情况下：)

stuff = function (thing, callback) {
  var inputs  = $('div.quantity > input').map(function(){
    var key   = this.attr('name')
     ,  value = this.attr('value')
     ,  ret   = {};

     ret[key] = value;
     return ret;
  }) 

  callback(null, inputs);
}