How to return True or False from function using Jquery asynchronous Ajax call

Question

I want the following function to return true or false based on my logic, but the function returning undefined.

function getUserData() {
    $.ajax({
    type: 'POST',
    contentType: 'application/json',
    url: 'myservice',
    dataType: "JSON",
    success: function (data) {
        if (data.d.UserID > 0) {
            return true;
        } else {
            return false
        }
        return false;
    },
    error: function (error) {
        return false;
    }
});};
if (getUserData()) {
//do something
} else {
//redirect
}

please do not consider it a duplicate, it is different, I dont want to return the callback functions I want to return true or false based on those callback functions.

Please put the action code, from where you are getting the data or at least show us what output/response you are getting from the server. — Abhishek Dhanraj Shahdeo, Mar 15 '16 at 08:33
server is doing fine and returning my data, but I am unable to return these true or false to getUserData() — Khalil, Mar 15 '16 at 08:40
Yesndreas you are right. but I want to decide my logic here in this function not want to repeat my logic everywhere — Khalil, Mar 15 '16 at 08:45
It's asynchronous, so by definition, you *can't* get the result back until it's finished. That's what the *duplicate question* explains in depth: http://stackoverflow.com/a/14220323/2181514 — freedomn-m, Mar 15 '16 at 08:57
It's not clear why you think you need to "repeat logic everywhere" - that's what the callback function is for - you pass the logic function into the ajax wrapper. It's explained in the duplicate at this point: *"callback will refer to the function we pass to foo when we call it and we simply pass it on to success"* — freedomn-m, Mar 15 '16 at 08:59
I've to put my head down over this answer. I had not enough time to understand that so put my problem for direct solution — Khalil, Mar 15 '16 at 09:43

score 0 · Answer 1 · answered Mar 15 '16 at 08:51

0

Try this:

function getUserData(callback) {
    $.ajax({
        type: 'POST',
        contentType: 'application/json',
        url: 'myservice',
        dataType: "JSON",
        success: function (data) {
            if (data.d.UserID > 0) {
                callback(true);
            } else {
                callback(false);
            }
            callback(false);
        },
        error: function (error) {
            callback(false);
        }
    });
};

getUserData(function(status) {
    if (status) {
    //do something
    } else {
    //redirect
    }
});

answered Mar 15 '16 at 08:51

Deepak Biswal

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I try it Thanks, will post my feedback soon – Khalil Mar 15 '16 at 09:00
should callback(true) be callback = true – Khalil Mar 15 '16 at 09:04
didn't work but nonetheless thanks giving me your time – Khalil Mar 15 '16 at 09:36
what is not working? Are you not getting `status` value as true/false? – Deepak Biswal Mar 15 '16 at 09:39
yes console says status is not a function, by the way i have changed my code from yours so cant show you console detail any more – Khalil Mar 15 '16 at 09:44
when my page started it immediately said that the status is not a function before I call it – Khalil Mar 15 '16 at 09:46

score 0 · Answer 2 · answered Mar 15 '16 at 09:01

Use the below code may solve your issue: create a function and it should returns the defferd object.

  function AJAX(type,url){

   this.type=type;      // EX: GET , POST
   this.url=url;

this.invoke = function(){
var deferred = $.Deferred();
$.ajax({
    type: this.type,
    url: this.url,      
    contentType: 'application/json',
    dataType:"JSON"
    success: function(response){
        deferred.resolve(response);
    },
    error: function(exception){
        console.log("Ajax call returned error.");
         deferred.reject(exception);
    }
});

return deferred;

};
}

now call this function with proper parameters as below

 var ajax=new AJAX("POST","Your action");
 ajax.invoke().then(function(data){
       if(data==true){
         // Your code for true
          }else{
         // your code for false
         }
  });

now you can modify the functions as per your needs..

How to return True or False from function using Jquery asynchronous Ajax call

2 Answers2