如何使JavaScript中的函数参数不变? [英] How to make function parameter constant in JavaScript?
问题描述
我想做的是使用尽可能多的不可变变量,从而减少代码中移动部件的数量。我只想在需要的时候使用var和let。
What I want to do is to use as many immutable variables as possible, thus reducing the number of moving parts in my code. I want to use "var" and "let" only when it's necessary.
这不行:
function constParam(const a){
alert('You want me to '+a+'!');
}
任何想法?
推荐答案
函数参数将在ES6中保持可变绑定(如 var
),您无法做到这一点。您可能获得的最佳解决方案是将 参数
对象在 const
初始化:
Function parameters will stay mutable bindings (like var
) in ES6, there's nothing you can do against that. Probably the best solution you get is to destructure the arguments
object in a const
initialisation:
function hasConstantParameters(const a, const b, const c, …) { // not possible
…
}
function hasConstantParameters() {
const [a, b, c, …] = arguments;
…
}
请注意,此函数将具有不同的 code> .length ),如果需要,您必须声明一些占位符参数。
Notice that this function will have a different arity (.length
), if you need that you'll have to declare some placeholder parameters.
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