javascript - Array.prototype.forEach.call 给出 TypeError : Illegal invocation

Question

谁能告诉我为什么这不起作用？

Array.prototype.forEach.call(document.body.children, console.log);

我收到以下错误:

Uncaught TypeError: Illegal invocation(…)(anonymous function)

这似乎是无稽之谈，因为以下两者都有效:

Array.prototype.forEach.call(document.body.children, function () {console.log(arguments)});
Array.prototype.forEach.call(document.body.children, l=>console.log(l));

NOTE: the function being called (console.log in this case) is just an example, the original intent was to use document.body.removeChild instead, but this failed in the same way.

ANOTHER NOTE: I've only tried this in Chrome. I tried the following in a node.js console and it worked fine:

Array.prototype.forEach.call(myArray, console.log)

Answer 1

这是因为必须在 console 对象上调用 console.log 方法:

var log = console.log;
log(123); /* TypeError: 'log' called on an object that
             does not implement interface Console. */
log.call(console, 123); /* Works */

您可以通过将第三个参数传递给 forEach 来修复，该参数确定 this 值:

Array.prototype.forEach.call(document.body.children, console.log, console);

或者您可以将 console.log 绑定(bind)到 console:

Array.prototype.forEach.call(document.body.children, console.log.bind(console));

还有一个bind operator的提案:

Array.prototype.forEach.call(document.body.children, ::console.log);