分享一个简易的异步线程池，套娃式异步请求可用
本帖最后由 empyrealtear 于 2025-1-12 21:57 编辑# 简易异步线程池
## 1. 参考文献
- [如何实现一个简单的并发控制？](https://everfind.github.io/code-reading/async-pool.html)
## 2. 修改后代码
```js
const asyncPool = async (arr, process = (item, arr) => item, begin = (v) => v, end = (v) => v,
poolLimit = 10, percentComplete = (pct) => pct) => {
let ret = []
let executing = new Set()
let arr_res = new Array(arr.length)
let completeCount = 0
// begin
percentComplete(completeCount / arr.length * 100)
arr = begin(arr)
// process
for (let of arr.entries()) {
var p = Promise.resolve().then(async () => {
try {
let res = await process(item, arr)
arr_res = res
} catch (err) {
console.warn(err)
arr_res = err
}
return
}).finally(() => {
percentComplete((++completeCount) / arr.length * 100)
})
ret.push(p)
executing.add(p)
let clean = () => executing.delete(p)
p.then(clean).catch(clean)
if (executing.size >= poolLimit) {
await Promise.race(executing)
}
}
// end
return Promise.all(ret).then(() => {
percentComplete(completeCount / arr.length * 100)
return end(arr_res)
})
}
```
## 3. 使用样例
```js
fetch(url).then(async (xhr) => {
let data = xhr.response?.data
if (data) {
return await asyncPool(data, async (v, arr) => {
let row = {}
await fetch(v.url).then((xhr2) => {
let data2 = xhr2.response?.data
row = { value: data2 }
})
return row
})
}
})
```
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