我可以将 let 定义为变量，但它应该给出语法错误，因为 let 是关键字。另一方面，将 const 定义为变量会产生错误

Question

我正在研究 JavaScript 变量声明语法。

var

、

let

和

const

是声明变量的关键字。我尝试声明一个变量名

let

，这是一个关键字，并且定义成功。另一方面，我尝试将

const

定义为变量，但它给出了语法错误，这完全没问题。

我想知道为什么将

let

定义为变量时没有给出错误

浏览器信息：

Chrome 84.0.4147.105， 火狐79.0， Firefox 开发版 80.0b7

Answer 1

当创建 javascript 时，保留了大量关键字以供将来使用。这包括现在使用的东西，如

const

和

class

，以及一些尚未使用的东西（例如，

enum

）。 从一开始，你就不能用这些词作为标识符

let

不在该列表中，也不是“真正的”关键字。 因此，为了保持与添加

let

“关键字”之前编写的代码的向后兼容性，它需要可用作变量名称

Answer 2

黑色勾号*

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