JS模拟实现题目（new debounce throwee 等）

模拟new实现

function newObject() {

    let obj = new Object();

    let Con = [].shift.apply(arguments)

    obj.__proto__ = Con.prototype;

    let res = Con.apply(obj,arguments)

    return typeof res == "object" ? res : obj;

}

模拟instanceOf

function instanceOf(left,right) {

    let proto = left.__proto__;

    let prototype = right.prototype

    while(true) {

        if(proto == null) return false

        if(proto == prototype) return true

        proto = proto.__proto__;

    }

}

防抖 debounce

function debounce(fn,wait=50,immediate) {

    let timer;

    return function() {

        if(immediate) {

            fn.apply(this,arguments)

        }

        if(timer) clearTimeout(timer)

        timer = setTimeout(()=> {

            fn.apply(this,arguments)

        },wait)

    }

}

节流 throttle

function throttle(fn,wait=50) {

    let timer;

    return function() {

        if(!timer) {

            timer = setTimeout(()=> {

                fn.apply(this,arguments)

                timer = null

            },wait)

        }

    }

}

jsonp

function jsonp(url,callback,success) {

    let script = document.createElement("script")

    script.src = url;

    script.async = true;

    script.type = "text/javascript"

    window[callback] = function(data) {

        success && success(data)

    }

    document.body.append(script)

}

继承

function a() {

    this.a = "a"

}

a.prototype.test = function() {

    console.log(this.a)

}

function b() {

    a.call(this);

    this.b = "b"

}

function tmp() {}

tmp.prototype = a.prototype;

b.prototype = new tmp();

b.prototype.construcotr = b;

模拟call

Function.prototype.mycall = function(content = window) {

    content.fn = this;

    let args = [...arguments].slice(1);

    let result = content.fn(...args);

    delect content.fn;

    return result;

}

模拟apply

Function.prototype.myapply = function(content = window) {

    content.fn = this;

    let result;

    if(argument[1]) {

        result = content.fn(...argument[1]);

    } else {

        result = content.fn();

    }

    delect content.fn;

    return result;

}

模拟bind

Function.prototype.mybind = function(content) {

    if(typeof this != "function") {

        throw Error("not a function")

    }

    let fn = this;

    let args = [...arguments].slice(1);

    let resFn = function() {

        return fn.apply(this.instance == resFn ? this : content,args.concat(...arguments) )

    }

    function tmp() {}

    tmp.prototype = this.prototype;

    resFn.prototype = new tmp();

    return resFn;

}

巴特西

JS模拟实现题目（new debounce throwee 等）

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