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How do I return the response from an asynchronous call?
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How would I, using $.post() in a function, force the return on the post callback?
Example:
function myFunction(){
$.post(postURL,mydata,function(data){
return data;
});
}
I have tried playing around with it using .done() and .queue() however neither has worked for me.
I understand there is a fundamental flaw in my example; with that said, how can I achieve my desired functionality?
This is impossible. $.Ajax calls will always return immediately. You need to deal with the return when it is called through a callback (possibly several seconds later). Javascript never blocks for a given call. It may help to think of your code like this:
//This entirely unrelated function will get called when the Ajax request completes
var whenItsDone = function(data) {
console.log("Got data " + data); //use the data to manipulate the page or other variables
return data; //the return here won't be utilized
}
function myFunction(){
$.post(postURL, mydata, whenItsDone);
}
If you're interested more on the benefits (and drawbacks) of Javascript's no-blocking, only callbacks: this Node.js presentation discusses its merits in excruciating detail.
function myFunction(){
var deferred = new $.Deferred();
var request = $.ajax({
url: postURL,
data: mydata
});
// These can simply be chained to the previous line: $.ajax().done().fail()
request.done(function(data){ deferred.resolve(data) });
request.fail(function(){ deferred.reject.apply(deferred, arguments) });
// Return a Promise which we'll resolve after we get the async AJAX response.
return deferred.promise();
}
