Global Variable not updating through function

Question

With the given code -

var videowallwidth;
var videowallheight;
    function getPositions() {
   $.ajax({
       url: 'https://' + ipaddress + ':46272/NetAPICmd?Command=Output',
       type: 'get',
       data: '[]',
       dataType: 'jsonp',
       success: function (response1) {
           var msg1 = response1.Result;
           var testarray1 = msg1.split("\r\n");
           for (var i = 1; i <= testarray1.length - 1; i++) {
               var res = testarray1[i].split(':');
               var newRes = res;
               if (newRes[0] == "TotalSize") {
                   var ressplit = newRes[1].split('x');
                   videowallwidth = ressplit[0].trim(); 
                   videowallheight = ressplit[1].trim(); 
                  
                }
            }       
        }
    });
}

console.log(videowallwidth);

I have defined videowallwidth and videowallheight as global variables and set their values inside getPositions() function, When i console log the variables inside the function they seem fine and have the right values. But when i called them outside the function they show "undefined" which means their values didnt update globally... How do i fix this??

Can you show us how you declared the variables? – Luca Corsini Dec 28 '20 at 07:32 — Luca Corsini, Dec 28 '20 at 07:32
Edited it as per requested – CodingNoob Dec 28 '20 at 07:37 — CodingNoob, Dec 28 '20 at 07:37

score 0 · Answer 1 · answered Dec 28 '20 at 07:33

The callback function is asynchronous and you will get the correct value once the process is fully completed. To get the correct value, you need to log value inside the callback function.

 function getPositions() {
   $.ajax({
       url: 'https://' + ipaddress + ':46272/NetAPICmd?Command=Output',
       type: 'get',
       data: '[]',
       dataType: 'jsonp',
       success: function (response1) {
           var msg1 = response1.Result;
           var testarray1 = msg1.split("\r\n");
           for (var i = 1; i <= testarray1.length - 1; i++) {
               var res = testarray1[i].split(':');
               var newRes = res;
               if (newRes[0] == "TotalSize") {
                  var ressplit = newRes[1].split('x');
                  videowallwidth = ressplit[0].trim(); 
                  videowallheight = ressplit[1].trim(); 
                  console.log(videowallwidth, videowallheight);  // <------------------
               }
            }       
        }
    });
}

I understand what your saying but loggin inside doesnt do me any good i want to make the variables values accessible to other functions and not to only getPositions — CodingNoob, Dec 28 '20 at 07:38

score 0 · Answer 2 · answered Dec 28 '20 at 07:55

0

You might want to insert global variables inside the window object, like this:

window.videowallwidth = null;  //initialize as you please
window.videowallheight = null;  //initialize as you please

Like this, you should be sure they're reachable everywhere

Watch out with ajax, those functions are asynchronous, so you should use callbacks/promises etc.. to manage the "flow"

answered Dec 28 '20 at 07:55

Luca Corsini

738
4
20

I Tried setting it globally through 'window.variableName' and also tried setting the values inside the functions with window['variableName'] but doesnt seem to work. The variables are reachable, but they arent updated globally through the function – CodingNoob Dec 28 '20 at 07:59
wait: try to initialize them with a valid value, like 0. Are you still getting "undefined"? – Luca Corsini Dec 28 '20 at 08:00
No, if i initialise them globally, i am getting the global value so if its 0, the output i get is 0 and not the values that are updated inside the function.... – CodingNoob Dec 28 '20 at 08:03
Try to stop with a debugger after the line videowallheight = ressplit[1].trim(); Go into the debugger console, write window.videowallwidth; and see what it says. – Luca Corsini Dec 28 '20 at 08:06
Did it so the value of the variable changes inside the function but remains 0 outside the function – CodingNoob Dec 28 '20 at 08:13

Global Variable not updating through function

2 Answers2