Why 'datas' array is always empty?

Question

My code

 $.getJSON('/load4',
    function (data) {
        for (var i = 0; i < data.length; i++) {
            var counter = data[i];
            datas.push([counter.Id, counter.login.substr(0, 25),'3', counter.hash , 'MA']); 
        }
    });
console.log("Datas " + datas);

I'm trying to fill my array like [[a,b],[a,c]], but can't.

datas[i] = [counter.Id, counter.login.substr(0, 25),'3', counter.hash , 'MA'];

Also doesn't work.

add `console.log("Datas " + datas);` inside your `function` – Vipin Kumar Dec 05 '17 at 10:48 — Vipin Kumar, Dec 05 '17 at 10:48

score 0 · Answer 1 · answered Dec 05 '17 at 10:49

You have to put console.log inside your function instead of outside.

$.getJSON('/load4',
  function(data) {
    var datas = [];
    for (var i = 0; i < data.length; i++) {
      var counter = data[i];
      datas.push([counter.Id, counter.login.substr(0, 25), '3', counter.hash, 'MA']);
    }
    console.log("Datas " + datas);
  });

score 0 · Accepted Answer · answered Dec 05 '17 at 10:50

0

That's because you are loading your JSON asynchronously. Which means that the log runs before the callback function passed as parameter to getJSON.

answered Dec 05 '17 at 10:50

Yairopro

9,084
6
44
51

score -1 · Answer 3 · answered Dec 05 '17 at 10:45

-1

You have to create a variable datas first.

 var datas =[];   
 $.getJSON('/load4',
        function (data) {
            for (var i = 0; i < data.length; i++) {
                var counter = data[i];
                datas.push([counter.Id, counter.login.substr(0, 25),'3', counter.hash , 'MA']); 
            }
        });
console.log("Datas " + datas);

answered Dec 05 '17 at 10:45

Wilson

329
2
11

if it doesn't work share your program in a snippet. Or else share the json data format. thanks. – Wilson Dec 05 '17 at 10:45
1

That array will still be empty in the `console.log`. See the duplicate I linked to. – James Thorpe Dec 05 '17 at 10:46
1

`datas` will still be empty because the call to fill it is asynchronous. – phuzi Dec 05 '17 at 10:50

Why 'datas' array is always empty?

3 Answers3