Javascript: Create call back for function

Question

My requirement is very simple.

 subscribePresence();
 getValidationData();

getValidationData() must be called only when subscribePresence(); finishes its execution. is there any way of doing it ?

Answer 1

Pass getValidationData(); as callback function into first function .

Ex:

function subscribePresence(callback){
  //do your stuffs
  callback();
}

Now call your subscribePresence() as below

subscribePresence(getValidationData);