Async Function in loop - make variable available in inner function

Question

I am trying do an asynchronous call in a loop, use the returned result and also make the variable 'q' available to the inner function.

How would I make q available to to the inner function (with the same value as it was before async call)?

var oController = this;
for (var q = 0; q < dataArray.length; q++) {
  var InspectionNo = dataArray[q].inspectionNo;

  //async call
  oController._validateInspection(InspectionNo)

    //returns flag
    .then(function(flag) {
      debugger;
      if (flag) {
        //q is not defined here
        oController._doSomething(q)
      }
    });
}

`q` *will* be defined, and its value will be `dataArray.length`. — Pointy, Jul 17 '17 at 12:37
@Pointy thanks for your reply, I probably need to rephrase - I was looking for q at the time of calling the async call — neeko, Jul 17 '17 at 12:41
@neeko replacing this function(flag){ with (flag) => { might solve the issue. — Fahad Nisar, Jul 17 '17 at 12:43
@FahadNisar arrow functions retain the `this` context but not the variable in the loop. Replacing `var` with `let` is the way to go here, as mentioned by @Erazihel. — Frank Modica, Jul 17 '17 at 12:50

score 1 · Accepted Answer · answered Jul 17 '17 at 12:46

try something like this:

var oController = this;
for (var q = 0; q < dataArray.length; q++) {
            var InspectionNo = dataArray[q].inspectionNo;

            //async call
            Promise.all([oController._validateInspection(InspectionNo), q])

            //returns flag
            .then(function([flag, q]){
                    if(flag){
                        //q is not defined here
                        oController._doSomething(q)
                    }
                });
        }

Thanks! This is what I was looking for! – neeko Jul 17 '17 at 13:01 — neeko, Jul 17 '17 at 13:01

Async Function in loop - make variable available in inner function

1 Answers1