手写实现

1. 柯里化 curry

参考lodash 4.17.11 API 实现

• 使用bind拼接参数

function curry(fn) {
  const { length } = fn;

  return function next() {
    if (length === arguments.length) {
      return fn.apply(this, arguments);
    } else if (arguments.length < length) {
      return next.bind(this, ...arguments);
    }
  };
}

function abc(a, b, c) {
  return [a, b, c];
}

const curried = curry(abc);

console.info(curried(1)(2)(3)); //[1,2,3]
console.info(curried(1, 2)(3)); //[1,2,3]
console.info(curried(1, 2, 3)); //[1,2,3]

• 使用闭包将变量保存在curry函数中的container变量

function curry(fn) {
  const { length } = fn;
  let container = [];
  return function next() {
    const args = Array.prototype.slice.call(arguments);
    container = container.concat(args);
    if (length === container.length) {
      const ret = fn.apply(this, container);
      container = [];// 此处需要将保存参数的容器清空，连续调用curried函数，container参数不断增加
      return ret;
    } else if (container.length < length) {
      return next;
    }
  };
}

function abc(a, b, c) {
  return [a, b, c];
}

const curried = curry(abc);

console.info(curried(1)(2)(3)); //[1,2,3]
console.info(curried(1, 2)(3)); //[1,2,3]
console.info(curried(1, 2, 3)); //[1,2,3]