javascript - 这个javascript语法是什么意思 : const { headers, method, url } = request;

Question

这个问题在这里已经有了答案:





What do curly braces inside of function parameter lists do in es6?

(3 个回答)


4年前关闭。




不清楚这个语法是什么意思

const { headers, method, url } = request;

在这篇文章中找到 https://nodejs.org/en/docs/guides/anatomy-of-an-http-transaction/

Answer 1

它叫destructuring operator .

The destructuring assignment syntax is a JavaScript expression that makes it possible to unpack values from arrays, or properties from objects, into distinct variables.

简单的例子:

var obj={
   "a":2,
   "b":3
}
let {a,b}=obj;
console.log(a,b);

从你的例子中，我看到 request是一个对象，语句被翻译成

headers = request.headers

但您也可以申请 destructuring operator为 数组 .

var foo = [1, 2, 3];
var [one, two, three] = foo;
console.log(one);
console.log(two);
console.log(three);