JS 柯里化函数随笔

简洁版

function curry(fn) {
  return function curried(...args) {
    if (args.length >= fn.length) {
      return fn(...args);
    }
    return function(...args2) {
      return curried(...args.concat(args2));
    }
  };
}

var sum = (a, b, c) => a + b + c;
var cf = curry(sum);
cf(1, 2, 3);
cf(1, 2)(3);
cf(1)(2, 3);
cf(1)(2)(3);

 

 

更细致的模拟实现

const slice = Array.prototype.slice;
const curryMaker = function(fn, len) {
  const curriedArgs = slice.call(arguments, 2);
  return curry.apply(this, [fn, (len || fn.length), ...curriedArgs]);
};

const curry = function(fn, len) {
  const curriedArgs = slice.call(arguments, 2);
  return function() {
    const args = [...curriedArgs, ...arguments];
    // 如果与预期的参数长度一致，则执行函数，获取返回值
    if (args.length >= len) {
      return fn.apply(this, args);
    }
    // 否则，整理入参，返回curry函数的结果
    return curry.apply(this, [fn, len, ...args]);
  };
};

function calcSum() {
  return [...arguments].reduce((pre, value) => { return pre + value }, 0);
}
const calcSumCurry = curry(calcSum, 4);

const nextCalc = calcSumCurry(1, 2);
console.log(nextCalc(3)(4));