实现链式调用

昨日回顾

柯里化

function add(...args) {
  return args.reduce((a, b) => a + b, 0);
}
function curry(fn) {
  let args = [];
  return function temp(...newArgs) {
    if (newArgs && newArgs.length) {
      args = [...args, ...newArgs];
      return temp;
    } else {
      const result = fn.apply(this, args);
      args = [];
      return result;
    }
  };
}
const addCurry = curry(add);
console.log(addCurry(1)(2)(3)(4, 5)()); //15
console.log(addCurry(1)(2)(3, 4, 5)()); //15
console.log(addCurry(1)(2, 3, 4, 5)()); //15

今日解题

链式调用 -> 调用完方法将自身实例返回

/// 01
function Class1() {
  console.log("初始化");
}
Class1.prototype.method = function (param) {
  console.log(param);
  return this;
};
const c1 = new Class1();
// 由于new在实例化的时候this会指向创建的对象，所以this.method这个方法会在原型链中找到
c1.method("第一次调用")
  .method("第二次调用")
  .method("第三次调用")
  .method("第四次调用");

// 02
const obj = {
  a: function () {
    console.log("a");
    return this;
  },
  b: function () {
    console.log("b");
  },
};
obj.a().b();
// 03 类
class Math {
  constructor(value) {
    this.hasInit = true;
    this.value = value;
    if (!value) {
      this.hasInit = false;
      this.value = 0;
    }
  }
  add() {
    let args = [...arguments];
    let initValue = this.hasInit ? this.value : args.shift();
    const value = args.reduce((prev, curv) => prev + curv, initValue);
    return new Math(value);
  }
  minus() {
    let args = [...arguments];
    let initValue = this.hasInit ? this.value : args.shift();
    const value = args.reduce((prev, curv) => prev - curv, initValue);
    return new Math(value);
  }
}
let test = new Math();
test.add(222, 333, 444).minus(333, 222);

// 04 原型链
Number.prototype.add = function () {
  let _that = this;
  _that = [...arguments].reduce((prev, curv) => prev + curv, _that);
  return _that;
};
Number.prototype.add = function () {
  let _that = this;
  _that = [...arguments].reduce((prev, curv) => prev - curv, _that);
  return _that;
};
let num = 0;
let newNum = num.add(222, 333, 444).minus(333, 222);