In nodejs redo the task if promise failed until it reach maxLimit

Question

I have function which do NetowrkIO and network is not reliable in this case so here it may not work in first try so i need to retry if it failed here is pseudocode for it

count = 0
maxLimit = 10
success = false
while ( (success == false) && (count < maxLimit))
{
    try 
    {
        doNetworkIO(arg)
        success = true
    }
    catch(ex)
    {
        count += 1
    }
}

if( success == true )
{
    reportSuccess()
} else {
    reportFailure()
}

now i was trying to do it in nodejs. I searched and come up with promise as a way of doing it. But i don't no how to. here is my code.

var count = 0
var maxLimit = 10
doNetworkIO(arg)
    .then(reportSuccess)
    .catch(function () {
        if(count < maxLimit)
        {
            count += 1
            // => redo operation if count < limit
            // => help needed here
        }
        else {
            reportFailure()
        }
    })

here i am not sure to redo it once again.

if you have a different approach to task please share.

Answer 1

You can write a retry function, which will attach itself in the failure handler, like this

var count = 0;
var maxLimit = 10;

function tryNetworkIO() {
    if (count < maxLimit) {
        count += 1;
        return doNetworkIO(arg).then(reportSuccess).catch(tryNetworkIO);
    } else {
        reportFailure();
    }
}

Inspired by this answer, you can improve this a little bit, by attaching the reportSuccess only once at the end, when the promise really resolves, like this

var count = 0;
var maxLimit = 10;

function tryNetworkIO() {
    if (++count < maxLimit) {
        return doNetworkIO(arg).catch(tryNetworkIO);
    } else {
        throw new Error('Exceeded maximum number of retries');
    }
}

tryNetworkIO().then(reportSuccess).catch(reportFailure);