将此文件从.call（）传递给箭头功能 [英] Passing this from .call() to arrow function

问题描述

我有一个箭头功能，我试图用 call（）执行。为简化起见，如下：

I have an arrow function that I am trying to execute with call(). For the sake of simplification, as follows:

按预期运作

const func = (e) => {
    console.log(e)
}

func.call(null, e)

嗯...这里发生了什么？

我希望以下代码能够通过元素进入 func as this 。

I would expect the following code to pass element into func as this.

const func = (e) => {
    console.log(this)
    console.log(e)
}

func.call(element, e)

但是，此仍为 undefined 。

如果我将其切换为常规函数定义，则所有内容都按预期工作。

If I switch it to a regular function definition, all works as expected.

const func = function (e) {
    console.log(this)
    console.log(e)
}

func.call(element, e)

问题

为什么我无法将此的上下文从 call（）传递给箭头函数？

Why am I not able to pass a context for this into an arrow function from call()?

推荐答案

此未绑定在箭头函数中，所以 call（）和 apply（）只能传递参数。 忽略此

this is not bound in arrow functions, so call() and apply() can only pass in parameters. this is ignored

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions#Invoked_through_call_or_apply

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