Execute Promise.all in series

Question

I have an array that contains an array of promises, and each inner array could have either 4k, 2k or 500 promises.

In total there are around 60k promises and I may test it with other values as well.

Now I need to execute the Promise.all(BigArray[0]).

Once the first inner array is done, I need to execute the next Promise.all(BigArray[1]) and so on and so on.

If I try to execute a Promise.all(BigArray) its throwing:

fatal error call_and_retry_2 allocation failed - process out of memory

I need to execute it each of promises in series, not in parallel which I think that’s what Node its doing. I shouldn't use new libs however am willing to consider the answer!.

Edit:

Here is an example piece of code:

function getInfoForEveryInnerArgument(InnerArray) {
    const CPTPromises = _.map(InnerArray, (argument) => getDBInfo(argument));
    return Promise.all(CPTPromises)
        .then((results) => {
            return doSomethingWithResults(results);
        });
}
function mainFunction() {
    BigArray = [[argument1, argument2, argument3, argument4], [argument5, argument6, argument7, argument8], ....];
    //the summ of all arguments is over 60k...
    const promiseArrayCombination = _.map(BigArray, (InnerArray, key) => getInfoForEveryInnerArgument(InnerArray));

    Promise.all(promiseArrayCombination).then((fullResults) => {
        console.log(fullResults);
        return fullResults;
    })
}

Answer 1

Promise.all will not work, you could use Array.reduce to process BigArray elements, one by one:

BigArray.reduce((promiseChain, currentArray) => {
    return promiseChain.then(chainResults =>
        Promise.all(currentArray).then(currentResult =>
            [...chainResults, currentResult]
        )
    );
}, Promise.resolve([])).then(arrayOfArraysOfResults => {
    // Do something with all results
});