Javascript对象括号表示法（{Navigation} =）在左侧的分配 [英] Javascript object bracket notation ({ Navigation } =) on left side of assign

问题描述

我以前没有看到这个语法，我想知道这是什么。左侧的方括号引起了语法错误：unexpected token {

I haven't seen this syntax before and am wondering what it's all about. The brackets on the left are throwing a syntax error: "unexpected token {"

var { Navigation } = require('react-router');

我不知道webpack配置的哪个部分正在转换，语法的目的是什么。这是和谐的事吗？有人可以启发我吗？

I'm not sure what part of the webpack config is transforming or what the purpose of the syntax is. Is it a Harmony thing? Can someone enlighten me?

推荐答案

它被称为破坏分配，它是 ES2015标准。

解构赋值语法是一个JavaScript表达式，
使得可以从数组或对象中使用
语法反映了数组和对象文字的构造。

The destructuring assignment syntax is a JavaScript expression that makes it possible to extract data from arrays or objects using a syntax that mirrors the construction of array and object literals.

资料来源： 在MDN上结构化作业参考

对象解构

Object destructuring

 var o = {p: 42, q: true};
 var {p, q} = o;

 console.log(p); // 42
 console.log(q); // true 

 // Assign new variable names
 var {p: foo, q: bar} = o;

 console.log(foo); // 42
 console.log(bar); // true

数组解构

Array destructuring

var foo = ["one", "two", "three"];

// without destructuring
var one   = foo[0];
var two   = foo[1];
var three = foo[2];

// with destructuring
var [one, two, three] = foo;

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