Is this an acceptable method of avoiding callback hell in old versions of node?

Question

No promises, no async etc I wondered if this pattern is acceptable - my function is called and i'm passed a callback. I need to do 2 things before I can call that back:

function doSomething(..args.., callbackThatNeeds1And2DoneFirst){

    var done1 = false;
    var res1 = someAsync1(function call1callback(){ 
      //blah
      done1 = true;

      maybeComplete();
    });

    var done2 = false;
    var res2 = someAsync2(function call2callback(){ 
      //blah
      done2 = true;

      maybeComplete();
    });

    function maybeComplete(){
      if(done1 && done2){
        callbackThatNeeds1And2DoneFirst();
      }
    }

}

I suppose the questions is about variable scope - can multiple "concurrent" executions interfere with each other's values for done1 and done2, or does each call get its own variable scope?

Answer 1

Yes, this pattern is fine. It does basically what Promise.all does today, except that it works for exactly two asynchronous callbacks only not a variable amount.

Can multiple "concurrent" executions interfere with each other's values for done1 and done2, or does each call get its own variable scope?

Every call to doSomething creates a new scope with new done1 and done2 variables.