网站开发笔记--网站定制公司官网 - 高端网站建设

前端开发中树形结构转成列表

[ { id: 1, text: '节点1', parentId: 0, children: [ { id:2, text: '节点1_1&#3...

admin 2024-04-14 276 0

前端开发中列表转成树形结构

[ { id: 1, text: '节点1', parentId: 0 //这里用0表示为顶级节点 }, { id: 2, text: '节点1_1', pa...

admin 2024-04-13 297 0

前端开发中的dom转json

<div> <span> <a></a> </span> <span> <a></a> <a></a> </span></div>把上诉dom结构转成下面的JSON格式{ tag: 'DIV', children: [ { tag:...

admin 2024-04-12 211 0

前端面试题：每隔一秒打印 1,2,3,4

// 使用闭包实现for (var i = 0; i < 5; i++) { (function(i) { setTimeout(function() { console.log(i); }, i * 1000); })(i);}// 使用 let 块级作用域for...

admin 2024-04-11 323 0

前端开发实现Jsonp 封装

// 发送请求function createScript(src) { const script = document.createElement('script'); script.src = src; script.type = "text/javascript"; document...

admin 2024-04-10 345 0

sleep 函数

function sleep(time) { return new Promise(resolve => setTimeout(resolve, time));}// 使用sleep(1000).then(()=>{ console.log(1);})async function output() { let...

admin 2024-04-09 248 0

前端实现实现取消 promise

function cancel(promise) { const obj = {}; const p = new Promise((resolve, reject) => { obj.resolve = resolve; obj.reject = reject; }); obj.promise =...

admin 2024-04-08 220 0

实现 Promise.prototype.finally

Promise.prototype.finally = function(cb) { return this.then(res => { return Promise.resolve(cb()).then(() => res); }, err => { return Promise.resolve(cb...

admin 2024-04-07 191 0

实现 Promise.race

Promise.race = function(promises) { return new Promise((resolve, reject) => { for (let i = 0; i < promises.length; i++) { Promise.resolve(promises[i])....

admin 2024-04-06 237 0

实现 Promise.all(前端面试题)

Promise.all = function(promises) { return new Promise((resolve, reject) => { const result = []; let count = 0; if (promises.length === 0) { resolv...

admin 2024-04-05 263 0

实现 Promise

class Promise { constructor(fn) { this.status = 'pending'; this.onFulfilledCallbacks = []; this.onRejectedCallbacks = []; // 更改成功后的状...

admin 2024-04-04 279 0

前端开发中通用的ajax 封装

function ajax (url, method, postData) { return new Promise((resolve, reject) => { const xhr = new XMLHttpRequest(); xhr.open(method, url); xhr.setRequ...

admin 2024-04-03 154 0

发布订阅

class EventEmitter { constructor() { this.events = {}; } on(name, handler){ this.events[name] = this.events[name] || []; this.events[name].push(hand...

admin 2024-04-02 314 0

js数组去重

// 1.传统方式，遍历元素挨个比较，去重function uniqueArr(arr) { const res = []; const map = new Map(); for (let item of arr) { if (!map.has(item)) { res.push(...

admin 2024-04-01 302 0

前端开发中的浅拷贝

// Object.assignlet a = {a: 1, b: 2};let b = Object.assign({}, a);// ...let a = {a: 1, b: 2};let b = {...a};// slicelet a = [1, {a: 1}];let b = a.slice();// con...

admin 2024-04-01 261 0

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