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I have next code which load an file json, and make an array called questions.
if i do an console.log(JSON.stringify(questions)) inside getArray function it works ok, but if I do the same outsite the function it doesn't work, I tried with
alert(JSON.stringify(questions)) and alert(questions.length) it return [] and 0, where's my mistake??

var questions = [];
function getArray(){
    $.getJSON('questions.json', function (json) {
        for (var key in json) {
            if (json.hasOwnProperty(key)) {
                var item = json[key]; 
                questions.push({
                    Category: item.Category
                });
            }
        }
        //console.log(JSON.stringify(questions)); //it works
           return questions;
    });
}
$(document).ready(function(){
getArray();
});

alert(JSON.stringify(questions)) //return []
alert(questions.length) //return 0
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2
  • 1
    The issue is timing, as discussed in the previous answers. The alert()s are synchronous and execute before anything else because the rest is asynchronous and event-driven. Just because code is written in a particular order doesn't guarantee it executes in that same order, especially when working with events. Commented Feb 17, 2013 at 2:38
  • 2
    this gets asked 5 times a day... AJAX is asynchronous Commented Feb 17, 2013 at 2:39

1 Answer 1

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3

You can't use return because it's asynchoronous:

var callback = function(questions) {
    // Do something with questions here.
    alert(questions.length);
}

var questions = [];
function getArray(){
    $.getJSON('questions.json', function (json) {
        for (var key in json) {
            if (json.hasOwnProperty(key)) {
                var item = json[key]; 
                questions.push({
                    Category: item.Category
                });
            }
        }
        callback(questions);
    });
}
$(document).ready(function(){
getArray();
});
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