尽快输出

asap.js

const asyncFun = (i, cb) => {
    setTimeout(() => {
        let result = 2 * i
        cb(result)
    }, Math.random() * 1000);
}

const results = []
var rIndex = 1
const handle = (result, i) => {
    results[i] = result
    while (results[rIndex]) { // (results[rIndex]) 不能有0正常值
        console.log(rIndex + "," + results[rIndex++]);
    }
}

var total = 20;

for (let i = 1; i < total; i++) {
    ((j) => {
        asyncFun(j, (result) => {
            handle(result, j)
        })
    })(i)
}