为什么我应该使用块范围而不是函数范围？ [英] Why should I use block scope instead of function scope?

问题描述

功能范围对我来说完全没问题已有20年了。现在我到处读，我应该使用让和 const 而不是 var 。我想这主要是因为它是一个新功能。为什么我更喜欢块范围？

Function scoping was perfectly fine for me for 2 decades. Now I read everywhere, that I should use let and const instead of var. I guess this is mostly because it's a new feature. Why should I prefer block scope?

推荐答案

const 具有明显优势这是一个不断的约束。 让有一个临时死区，禁止重新声明同一范围内的标识符，因此有助于防止出现某些错误。

const has the obvious advantage that it's a constant binding. let has a temporal dead zone, and its forbidden to redeclare an identifier in the same scope, so it helps to prevent certain mistakes.

除此之外，当你不需要块范围时继续使用 var 没有任何问题。

Apart from those, there's nothing wrong with continuing to use var when you don't need a block scope.

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