Es2015的卷发腕带 [英] Curly Brakets in Es2015

问题描述

我正在阅读一些推文，我发现了这个推文Dan Abromov

I was reading some tweets and I came across this tweet by Dan Abromov

语法令我困惑。

const Font = ({ children }) => 
 <Block...

{} / strong>周围的孩子？显然它不是一个对象。我假定它的ES2015功能。

What is the point of { } around children? Clearly its not an object. I presume its ES2015 feature.

非常感谢

推荐答案

破坏绑定模式。它表示参数 children 应绑定到传递给函数的对象的 children 属性的值。

It's a destructuring binding pattern. It indicates that the parameter children should be bound to the value of the children property of an object passed to the function.

在ES2015环境中尝试这样做：

Try this in an ES2015 environment:

function x({ foo }) {
  console.log(foo);
}

x({ hello: "world", foo: "bar", well: "that's all"});

字符串bar将被记录到控制台，因为这是foo的值传递给函数的对象的属性。

The string "bar" will be logged to the console, because that's the value of the "foo" property of the object passed to the function.

如果传递给函数的值是没有children属性的对象，如果它不是一个对象，那么参数将为 undefined 。

If the value passed to the function is an object with no "children" property, of if it's not an object at all, then the parameter will be undefined.

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