promse 并发

const fn = function (time) {
    return () => {
        return new Promise((resolve) => {
            setTimeout(() => {
                console.log(Date.now() + ':' + time);
                resolve(time);
            }, time * 1000);
        })
    }
}

const fnArray = [];
for (let i = 0; i < 10; i += 1) {
    fnArray.push(fn(i));
}

const schedule = async (fnArray, limit) => {
    const dataReult = [];
    const runStack = [...fnArray];
    let startNewIndex = limit - 1;
    const run = async (fn, index, retry = 3 ) => {

        if (index > fnArray.length - 1 ){
            return;
        }

        if (startNewIndex > fnArray.length - 1 ){
            return;
        }

        if (!retry) {
            dataReult[index] = -1;
            return;
        }

        try {
            const data = await fn();
            dataReult[index] = data;
        } catch (err) {
            console.error(err);
            return run(fn, index, retry--);
        }

        startNewIndex++;
        
        const newFn = runStack[startNewIndex];
        const newRetry = 3;
        return run(newFn, startNewIndex, newRetry)
    }
    
    const fns = [];
    for (let i = 0; i < limit; i++) {
        fns.push(run(fnArray[i], i, 3));
    }
    await Promise.all(fns);

    console.log(dataReult);
}

schedule(fnArray, 2);