Array values not defined

Question

I want to read from a json file and use its values to draw triangles. While being in the routine i can print out the value, outside of it, it won't work any more. My code:

faces=new Array(40000);
$.getJSON('file.json', function(data) {
   $.each(data.faces, function(i, f) {
faces[i]=new Array(3);
faces[i][1]=data.faces[i].f1;
faces[i][2]=data.faces[i].f2;
faces[i][3]=data.faces[i].f3;
 //alert(faces[1][1]); works here
 });
 });
 //alert(faces[1][1]); doesn't work here, console says faces[1][1] is undefined

How can I fix this?

intuitivepixel · Accepted Answer · 2013-08-27 08:09:42Z

2

The call to $.getJSON is asynchronous, you only have your faces array populated inside the callback as you already noticed.

What you could do is:

faces=new Array(40000);
$.getJSON('file.json', function(data) {
  $.each(data.faces, function(i, f) {
    faces[i]=new Array(3);
    faces[i][1]=data.faces[i].f1;
    faces[i][2]=data.faces[i].f2;
    faces[i][3]=data.faces[i].f3;
     //alert(faces[1][1]); works here
  });
  someFunction();
});

someFunction() {
  alert(faces[1][1]);
}

Hope it helps.

answered Aug 27, 2013 at 8:09

intuitivepixel

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Comments

André Leal · Accepted Answer · 2013-08-27 08:11:08Z

0

That happens because getJSON is async.

try to use the jquery ajax method with async property defined.

   $.ajax({
        type: "GET",
        url: remote_url,
        async: false,
        success : function(data) {
            remote = data;
        }
    });

answered Aug 27, 2013 at 8:11

André Leal

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Comments

Grant Thomas · Accepted Answer · 2013-08-27 08:11:09Z

0

Your call to actually get the JSON, in the second case, is taking longer than it takes to get to the point of usage outside of the "success"/"complete" callback, due to the asynchronicity of getJSON, so the value(s) is/are naturally undefined until the function returns, hence the "success"/"complete" function.

answered Aug 27, 2013 at 8:11

Grant Thomas

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Comments

Manu M · Accepted Answer · 2013-08-27 08:12:00Z

-1

Simple change,

faces=new Array(40000);
$.getJSON('file.json', function(data) {
 $.each(data.faces, function(i, f) {
  faces[i]=new Array(3);
  faces[i][1]=f.f1;
  faces[i][2]=f.f2;
  faces[i][3]=f.f3;
 });
});

Use f instead of data.faces inside $.each

answered Aug 27, 2013 at 8:12

Manu M

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1 Comment

Manu M Over a year ago

what is wrong in it u need to use data.faces inside each function since u already assigned its each index in a variable f

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