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38 lines (36 loc) · 979 Bytes
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Copy pathconcurrent.js
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38 lines (36 loc) · 979 Bytes
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/*
run(fetchList, num, callback);
fetchList 接口请求list
num 最大并发数
callback 所有接口返回后，执行callback，并把接口返回值回传
*/
const fetch = (val, time) => {
return () => new Promise((resolve, reject) => {
setTimeout(() => {resolve(val)}, time)
})
}
const fetchList = [fetch(1, 1000), fetch(2, 2500), fetch(3, 1000), fetch(4, 2000), fetch(5, 1000)];
// 1, 3, 2, 5, 4
const run = (list, num = 2, callback) => {
let index = 0;
const res = [];
const excute = () => {
while(index < 2 && list.length) {
const fn = list.shift();
fn().then(r => {
index--;
res.push(r);
if(index === 0 && !list.length) {
callback(res);
}
excute();
})
index++;
}
}
excute();
}
run(fetchList, 2, (result) => {
console.log("result", result);
// 1, 3, 2, 5, 4
})