| 5 | // } |
| 6 | |
| 7 | function limit(maxCount){ |
| 8 | // [,5] |
| 9 | // [2,34,] |
| 10 | let queue = [] |
| 11 | let activeCount = 0 |
| 12 | |
| 13 | const next = ()=>{ |
| 14 | //下一个任务 |
| 15 | activeCount-- |
| 16 | if(queue.length>0){ |
| 17 | queue.shift()() |
| 18 | } |
| 19 | } |
| 20 | const run = async (fn,resolve,args)=>{ |
| 21 | //执行一个函数 |
| 22 | activeCount++ |
| 23 | const result = (async()=>fn(...args))() |
| 24 | resolve(result) |
| 25 | await result |
| 26 | next() //下一个 |
| 27 | } |
| 28 | const push = async (fn,resolve,args)=>{ |
| 29 | queue.push(run.bind(null,fn,resolve,args)) |
| 30 | if(activeCount<maxCount && queue.length>0){ |
| 31 | // 队列没满 并且还有任务 启动任务 |
| 32 | queue.shift()() |
| 33 | } |
| 34 | } |
| 35 | |
| 36 | let runner = (fn,...args)=>{ |
| 37 | return new Promise((resolve)=>{ |
| 38 | push(fn,resolve,args) |
| 39 | }) |
| 40 | } |
| 41 | return runner |
| 42 | |
| 43 | |
| 44 | } |
| 45 | async function sleep(n,name='test'){ |
| 46 | return new Promise(resolve=>{ |
| 47 | console.log(n,name,'start') |