【手写篇 - Day 01】手写函数柯里化

[MarsPen]

题目描述

function curry (func) {
  // 此处补全
}

function sum(a, b, c){
  return a + b + c
}

let currySum = curry(sum)
console.log(currySum(1,2,3)) // 6 still callable normally
console.log(currySum(1)(2,3)) // 6 currying of 1st arg
console.log(currySum(1)(2)(3)) // 6 full currying

[MarsPen]

思路

• 获取参数的形参数个数
• 返回一个闭包，利用延迟执行函数不断的执行并返回接受余下的参数直到调用结束

代码

// 实现一
function curry(func) {
  return function curried(...args) {
    if (args.length >= func.length) {
      return func.apply(this, args)
    } else {
      return function(...args2) {
        return curried.apply(this, args.concat(args2))
      }
    }
  }
}

function sum(a, b, c){
  return a + b + c
}

let currySum = curry(sum)
console.log(currySum(1,2,3)) // 6 still callable normally
console.log(currySum(1)(2,3)) // 6 currying of 1st arg
console.log(currySum(1)(2)(3)) // 6 full currying

// 实现二
function curry (func) {
  return new Proxy(func, {
    apply(target, thisArg, args) {
      return (args.length >= target.length) ?
        Reflect.apply(...arguments) :
        curry(target).bind(thisArg, ...args);
    }
  })          
}

知识补充

• 什么是柯理化