前端手写

author: @linkaimin

Function.prototype.Call = function (context) {
    let cxt = context || window
    cxt.fn = this; 
    let args = [...arguments].slice(1) 
    let res = arguments.length > 1?cxt.fn(args):cxt.fn()
    delete cxt.fn 
    return res;
}

Function.prototype.Apply = function (context) {
    let cxt = context || window;
    cxt.fn = this;
    let args = [...arguments][1];
    res = arguments[1] ? cxt.fn(args):cxt.fn();
    delete cxt.fn;
    return res
}

Function.prototype.Bind = function (context) {
    if (typeof this !== 'function') {
        return;
    }
    let that = this;
    let args = [...arguments].slice(1);
    function fn() {
        let self = this instanceof that ? this : context;
        let addArgs = [...arguments];
        return that.apply(self, [...args, ...addArgs]);
    }
    fn.prototype = this.prototype;
    return fn;
}

function New(Obj,...args){
    let obj = Object.create(Obj.prototype);
    Obj.apply(obj,args); 
    return obj; 
  }

function deepClone1(obj) {
    var objClone = Array.isArray(obj) ? [] : {};
    if (obj && typeof obj === "object") {
      for (key in obj) {
        if (obj.hasOwnProperty(key)) {
          if (obj[key] && typeof obj[key] === "object") {
            objClone[key] = deepClone1(obj[key]);
          } else {
            objClone[key] = obj[key];
          }
        }
      }
    }
    return objClone;
}

function debounce(func, wait) {
    let timer;
    return function() {
      let context = this; 
      let args = arguments;
      if (timer) clearTimeout(timer);
      timer = setTimeout(() => {
        func.apply(this, args)
      }, wait)
    }
}

function throttle(func, wait) {
    let timeout;
    return function() {
      let context = this;
      let args = arguments;
      if (!timeout) {
        timeout = setTimeout(() => {
          timeout = null;
          func.apply(context, args)
        }, wait)
      }
    }
}

class MyPromise {
    constructor(executor) {
      this.$state = 'PENDING';
      this.$value= null;
      const resolve = res => {
        if (this.$state !== 'PENDING') {
          return;
        }  
        this.$state = 'FULFILLED';
        this.$value = res; 
        return res;
      };
      const reject = err => {
        if (this.$state !== 'PENDING') {
          return;
        }
        this.$state = 'REJECTED';
        this.$value = err;
      };
      try {
        executor(resolve, reject);
      } catch (err) {
        reject(err);
      }
    };
}

function sumBigNumber(a, b) {
    let res = '';
    let temp = 0;
    a = a.split(''),
        b = b.split('')
    while (a.length || b.length || temp) {
        temp = temp + ~~a.pop() + ~~b.pop();
        res = temp % 10 + res;
        temp = temp > 9;
    }
    return res
}

function jsQuickSort(array) {
    if (array.length <= 1) {
        return array;
    }
    const pivotIndex = Math.floor(array.length / 2);
    const pivot = array.splice(pivotIndex, 1)[0]; 
    const left = [], right = [];
    array.forEach(item => {
        if (item < pivot) {  
            left.push(item); 
        } else {  
            right.push(item);
        }
    });
    return jsQuickSort(left).concat(pivot, jsQuickSort(right));  
}