Asynchronous for cycle in JavaScript

Question

I need a loop that waits for an async call before continuing. Something like:

for ( /* ... */ ) {

  someFunction(param1, praram2, function(result) {

    //         


        

Answer 1

Given an asynchronous worker function someFunction that will call back a result function with a result argument saying whether or not the loop should continue:

// having:
// function someFunction(param1, praram2, resultfunc))
// function done() { alert("For cycle ended"); }

(function(f){ f(f) })(function(f){
  someFunction("param1", "praram2", function(result){
    if (result)
      f(f); // loop continues
    else
      done(); // loop ends
  });
})

In order to check whether or not to end the loop, the worker function someFunction can forward the result function to other asynchronous operations. Also, the whole expression can be encapsulated into an asynchronous function by taking a function done as callback.