Banks1y

```javascript //promise then function Traficlight(light,timer){ return new Promise((resolve,reject)=>{ setTimeout(()=>{ console.log(light); resolve() },timer) }) } const step = ()=>{ Traficlight('red',3000).then(()=>Traficlight('yellow',2000)).then(()=>Traficlight('green',1000)).then(step) } step() //async await function Traficlight(light,timer){ return new Promise((resolve,reject)=>{ setTimeout(()=>{ console.log(light);...

```javascript // console.log(JSON.stringify(Object.assign(obj1, obj2))) //不用Object.assign function myAssign(obj, ...src) { for (let i = 0; i < src.length; i++) { if (src[i] !== null || src[i] !== undefined) { for (let...

```javascript //Promise串行 async function serialPromise(taskarr) { let res = []; for (const task of taskarr) { try { res.push(await task()); } catch (err) { res.push(null); } } return res; }...

```javascript //JS异步数据流，实现并发异步请求，结果顺序输出 const timer = [3000, 2000, 1000, 5000, 5000]; function myTimeout(timer) { return new Promise((resolve, reject) => { setTimeout(() => { resolve(timer); }, timer); }); } async function orderPrint(timer)...

```javascript const str = "ABCabc123"; let res = str.split("").reduce((pre, cur) => { if (!pre[cur]) pre[cur] = 1; else pre[cur]++; return pre; }, {}); console.log(res); ```