模拟new实现

    1. function newObject() {
    2.     let obj = new Object();
    3.     let Con = [].shift.apply(arguments)
    4.     obj.__proto__ = Con.prototype;
    5.     let res = Con.apply(obj,arguments)
    6.     return typeof res == "object" ? res : obj;
    7. }

    模拟instanceOf

    1. function instanceOf(left,right) {
    2.     let proto = left.__proto
    3.     let prototype = right.prototype
    4.     while(true) {
    5.         if(proto == null) return false
    6.         if(proto == prototype) return true
    7.         proto = proto.__proto
    8.     }
    9. }

    防抖 debounce

    1. function debounce(fn,wait=50,immediate) {
    2.     let timer;
    3.     return function() {
    4.         if(immediate) {
    5.             fn.apply(this,arguments)
    6.         }
    7.         if(timer) clearTimeout(timer)
    8.         timer = setTimeout(()=> {
    9.             fn.apply(this,arguments)
    10.         },wait)
    11.     }
    12. }

    节流 throttle

    1. function throttle(fn,wait=50) {
    2.     let timer;
    3.     return function() {
    4.         if(!timer) {
    5.             timer = setTimeout(()=> {
    6.                 fn.apply(this,arguments)
    7.                 timer = null
    8.             },wait)
    9.         }
    10.     }
    11. }

    jsonp

    1. function jsonp(url,callback,success) {
    2.     let script = document.createElement("script")
    3.     script.src = url;
    4.     script.async = true;
    5.     script.type = "text/javascript"
    6.     window[callback] = function(data) {
    7.         success && success(data)
    8.     }
    9.     document.body.append(script)
    10. }

    继承

    1. function a() {
    2.     this.a = "a"
    3. }
    4. a.prototype.test = function() {
    5.     console.log(this.a)
    6. }
    8. function b() {
    9.     a.call(this);
    10.     this.b = "b"
    11. }
    13. function tmp() {}
    14. tmp.prototype = a.prototype;
    15. b.prototype = new tmp();
    16. b.prototype.construcotr = b;

    模拟call

    1. Function.prototype.mycall = function(content = window) {
    2.     content.fn = this;
    3.     let args = [...arguments].slice(1);
    4.     let result = content.fn(...args);
    5.     delect content.fn;
    6.     return result;
    7. }

    模拟apply

    1. Function.prototype.myapply = function(content = window) {
    2.     content.fn = this;
    3.     let result;
    5.     if(argument[1]) {
    6.         result = content.fn(...argument[1]);
    7.     } else {
    8.         result = content.fn();
    9.     }
    10.     delect content.fn;
    11.     return result;
    12. }

    模拟bind

    1. Function.prototype.mybind = function(content) {
    2.     if(typeof this != "function") {
    3.         throw Error("not a function")
    4.     }
    5.     let fn = this;
    6.     let args = [...arguments].slice(1);
    8.     let resFn = function() {
    9.         return fn.apply(this.instance == resFn ? this : content,args.concat(...arguments) )
    10.     }
    11.     function tmp() {}
    12.     tmp.prototype = this.prototype;
    13.     resFn.prototype = new tmp();
    15.     return resFn;
    16. }