Javascript function class object returning undefined

Question

Hi Guys I have function and it's returning a javascript class but at runtime returning value is undefined. When I set return value to some global variable and it's gave me right result on Chrome developer console. Why is that happening?

var globalData;

$(document).ready(function(){

var request = postRequest("contact", dt, elem);

        globalData = request;

        console.log(request.status); //this gaves me undefined

});


function returnObj(status, message, projects) {
    this.status = status;
    this.message = message;
    this.projects = projects;
}



function postRequest(method, vars, elem) {

    var result = new returnObj();

    $.post('api.aspx',
        {
            method: "test"
        },
        function (data, status) {
            var resultObject = $.parseJSON(data);

            result.status = resultObject.status;
            result.message = resultObject.message;
            result.projects = resultObject.projects;


        });

    return result;

}

http://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call — naortor, Feb 19 '17 at 11:48
The post is async, when function return "result" the post surely is not yet finish ! — Baro, Feb 19 '17 at 11:51

Mihai Alexandru-Ionut · Accepted Answer · 2017-02-19T12:10:31.820

2

Your post ajax request accepts as a third parameter a callback function which is asyncronous.

return result; statement will be called before the callback is finished and that's the reason you're receiving undefined.

I recommend you to create a callback function.

function postRequest(method, vars, elem,callback) {
                                        ^^^^^^^^
     var result = new returnObj();
     $.post('api.aspx',
      {
        method: "test"
      },
      function (data, status) {
          var resultObject = $.parseJSON(data);
          result.status = resultObject.status;
          result.message = resultObject.message;
          result.projects = resultObject.projects;
          callback(result);
     });
}

How to call function:

postRequest(method, vars, elem, function(result) { 
    console.log(result);
});

edited Feb 19 '17 at 12:10

answered Feb 19 '17 at 11:51

Mihai Alexandru-Ionut

47,092
13
101
128

Why some people downvotes the correct answer ?? – Mihai Alexandru-Ionut Feb 19 '17 at 12:07
Not my downvote, but you can't return a value from the callback. – JJJ Feb 19 '17 at 12:09
@JJJ, yes,sorry, my mistake. – Mihai Alexandru-Ionut Feb 19 '17 at 12:10
thanks you so much. it works – PsyGnosis Feb 19 '17 at 12:20

Javascript function class object returning undefined

1 Answers1