Question

38

JavaScript get data from json to a global variable

rated 0 times [ 44] [ 6] / answers: 1 / hits: 35704 / 10 Years ago, wed, july 23, 2014, 12:00:00

function test(){

    $.getJSON( notebook-json-data.php, function( data ) {

       var myData = data;

    });

 }

Here in my function i get json objects, but i want to access myData variable from out side the scope of its function.

I have tried setting var myData outside the function but no luck.. :(

I am not familiar with JSON, did i need any parsing?

how to set this variable as global??

Please help...

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cherish

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answered 10 Years ago dominiqued · Accepted Answer

Don't try to set myData as a global variable - it won't work because getJSON is asynchronous. Either use a promise:

function test() {

  return $.getJSON('notebook-json-data.php');

}



$.when(test()).then(function (data) {

  console.log(data);

});

Or a callback:

function test(callback) {

  $.getJSON('notebook-json-data.php', function (data) {

    callback(data);

  });

}



test(function (data) {

  console.log(data);

});

Edit

Since you want to use the data in other areas of your code, use a closure to create an environment where your variables don't leak out into the global space. For example, with the callback:

(function () {



  var myData;



  function test(callback) {

    $.getJSON('notebook-json-data.php', function (data) {

      callback(data);

    });

  }



  test(function (data) {

    myData = data;

    autoPopulate('field', 'id');

  });



  function autoPopulate(field, id) {

    console.log(myData);

  }



});

myData is cached as a global variable specific to that closure. Note the other functions will only be able to use that variable once the callback has completed.