如何在JavaScript中构造无限fun（）（）（）...（）（）？ [英] How can I construct a infinite fun()()()...()() in JavaScript?

问题描述

只是一个奇怪的问题。我想创建一个可以处理无限层的函数？ make add（2）（3），add（1）（2）（3）...（10）all works。

Just a curious question. I want to create a function can handle infinite "layer"? make add(2)(3), add(1)(2)(3)...(10) all works.

任何想法？

推荐答案

你可以轻微抓住。返回值必须是您可以强制转换为数字的函数。方法如下：

You can, with a slight catch. The return value must be a function that you can coerce to a number. Here's how:

function add (addend) {
  'use strict'
  const sum = (this || 0) + addend
  const chain = add.bind(sum)

  for (const prop of Object.getOwnPropertyNames(Number.prototype)) {
    chain[prop] = Number.prototype[prop].bind(sum)
  }

  return chain
}

console.log(add(1))
console.log(add(1)(2))
console.log(add(1)(2)(3))
// convinced yet?
let four = add(4)
console.log(typeof four, four === 4)
// it's a function, not a number, so coerce to a primitive first
four = Number(four)
console.log(typeof four, four === 4)

add（）是一个包含上下文（<$ c）的函数$ c>此）和所有 Number.prototype p属性，包括其 Symbol.toPrimitive 属性。在严格模式中，上下文表现得更多很好，允许你将它定义为一个原始值，如数字，而不是默认为窗口并强制绑定基元到对象 s。

add() is a function that contains its context (this) and all the Number.prototype properties, including its Symbol.toPrimitive property. In strict mode, the context behaves a lot more nicely, allowing you to define it as a primitive value like a number instead of defaulting to window and coercing bound primitives to Objects.

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