m0_53612276的博客

console.log(typeof undefined);console.log(typeof '123');console.log(typeof 123);console.log(typeof true);console.log(typeof new Symbol(123));console.log(typeof function(){});console.log(typeof {});// undefined// string// number// boolean// func.

1、四舍五入的情况var num =2.446242342;num = num.toFixed(2); // 输出结果为 2.452、不四舍五入Math.floor(15.7784514000 * 100) / 100 // 输出结果为 15.77

let map = new Map();map.set('hello', 'world');map.set('1+1', '2');map.set('红楼梦', '罗贯中');console.log('======方式1=======');map.forEach((value, key) => { console.log(value, key);})// world hello// 2 1+1// 罗贯中 红楼梦 console.log('======方式2==.

/** * 事件订阅,发布,取消订阅 */export class EventManager { events = {}; subscribe(name, func) { if (!this.events[name]) { this.events[name] = [] } this.events[name].push(func) } publish(name) { if (this.events[name]) { this..

探究 npm ws 这个库1. 搭建实验环境创建项目 ws-serve ws-clientws-serve 执行命令npm init -ynpm install --save wsmain.js 内容const WebSocket = require('ws')const WebSocketServer = WebSocket.Server;const wss = new WebSocketServer({ port: 8080 });wss.on('connection',

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