JavaScript Promise Chaining in lightning component has transaction issue in server side

Question

I have a requirement , where I want to call server methods multiple times passing some value as parameter. I have used javascript promise to call the methods one after another using .then When I am running my piece of code two issues I am facing.

1. In each then I have a server call . So I have used $A.getCallback but the resolve result is coming as undefined and actual server logic from the first promise executes in some fraction of delay thus result is coming as undefined.

2. In all the then I have one DML statement , So ideally for each promise there has to be separate transaction but in salesforce debug log all DML from all promises comes under one transactional limit.

PFB snippet:

Promise.resolve()
    .then($A.getCallback(
        function () {
            //client side data manipulation

            return (0);
        }))
    .then($A.getCallback(function recursiveFunction(
        recIndex) {
        //recursive promise logic

        if (somecondition) {

            //call server
            //helper.submethodcalled
            //if success with the sub method then only go for recursion or else stop
            var promise = Promise.resolve()
                .then(
                    function () {
                        console.log('inside rec loop**');
                        return (recursiveFunction(some increment /
                            decrement condition)); // RECURSE!
                    }
                );
            return (promise);

        } else {
            return (0);
        }
    }))
    .then($A.getCallback(function () {
        //final block
    }))
    .catch(function (error) {
        console.log('Failure : ' + error.message);
    });

Answer 1

Thanks for the answer , but I was able to solve both the issues.Instead of recursive promise I am now using java script array.reduce method I was facing by following approach. Please find my below answer in pseudo code.

function: promiseChainingMethod(component, groups) {
    var promise = groups.reduce(

        function reducer(promiseInst, value) {
            var nextThenChain = promiseInst.then(
                function(resultValue) {
                    console.log('do some checking with value return from last promise****' + resultValue);
                    //call your helper logic which has return type of promise with $A.getCallback
                    var apexMethodResult = this.subMethod(component, value);
                    return (apexMethodResult);
                }
            );
            return (nextThenChain);
        },
        Promise.resolve(0) //This will start the promise with 0 value   

    ).then($A.getCallback(function(ress) {
        console.log('final block***' + ress); //post array execution logic , if needed
        console.groupEnd();
    })).catch(function(error) {
        console.log('Failure : ' + error.message); //error handling
    });
},

//helper method to call server and get DML result status
function: subMethod(component, listData) {
    retutn new Promise($A.getCallback(function(resolve, reject) {
        //server call
        var result = //server return data
            if (success)
                resolve(result);
    }));
}

Now my promise is working as expected and for each server call separate transaction is being generated , which was my 2nd issue.