推导链

Q1: 需求？→ 红3s → 绿2s → 黄1s → 循环 Q2: 怎么串行？→ async/await 或 Promise 链 Q3: 怎么循环？→ 递归或 while(true)

代码

const sleep = (ms) => new Promise(r => setTimeout(r,ms))

async function trafiicLight() {
    while(true) {
        console.log('🔴 红灯')
        await sleep(3000)
        console.log('🟢 绿灯')
        await sleep(2000)
        console.log('🟡 黄灯')
        await sleep(1000)
    }
}