Defering return statement

Question

Possible Duplicate:
JavaScript asynchronous return value / assignment with jQuery

I need a prototype of chart with constructor, so I wrote this:

function Chart(file) {
  var chart = undefined

  $.getJSON(file, function(data) {

    chart = {
      categories: data.keys
      series: [{
          name: 'first',
          data: data.first
        }, {
          name: 'second',
          data: data.second
      }]
    }

  });

  return chart
}

Then I realized, that because of JaavScript's synchronousness it returns undefined. How should I defere the return statement of Chart?

Answer 1

1.) Specify a callback function

function Chart(file, callback) {
  var chart = undefined

  $.getJSON(file, function(data) {

    chart = {
      categories: data.keys
      series: [{
          name: 'first',
          data: data.first
        }, {
          name: 'niewykopane',
          data: data.first
      }]
    }
    callback(chart);

  });
}

2.) Synchronous request (not recommended!)

You could use $.ajax() and set the async property to false.

Warning: This method is not recommended! It blocks the whole UI, all other JavaScript and timers until the request is finished!