jquery each json variable bug

Question

I have a strange bug. When I try to run my code:

var firstJson;
$.getJSON(site_url+"/more/sector_by_city/"+id+"?"+Math.random(), function( json ) { 
    $.each(json, function(key, value) {
        firstJson = 9;  
    });
}); 
alert(firstJson);

The alert I get is: "undefined".

Why did I get this instead of getting 9?

What am I missing here?

(the each loop runs without issue and there are values in the JSON) At the end, 9 changes to some other value.

Thanks

tymeJV · Accepted Answer · 2013-06-25 15:28:43Z

6

Async functions my friend. Your alert is being called before your .getJSON request has been finished. You'll need to use a callback function to get the correct alert.

answered Jun 25, 2013 at 15:28

tymeJV

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ayyp · Accepted Answer · 2013-06-25 15:29:25Z

4

Because when you call alert(firstJson) the asynchronous $.getJSON call has not yet completed, so firstJson has no value associated with it. If you move your alert into the $.each function or after the $.each, and at the end of $.getJSON, it will have a value.

answered Jun 25, 2013 at 15:29

ayyp

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Comments

krishwader · Accepted Answer · 2013-06-25 15:32:55Z

2

The variable doesnt have a value when alert is called. You'll have to wait getJSON is over, using done().

var firstJson;
$.getJSON(site_url+"/more/sector_by_city/"+id+"?"+Math.random(), function( json ) { 
    $.each(json, function(key, value) {
        firstJson = 9;  
    });
}).done(function() {
   alert(firstJson);
});

References:

answered Jun 25, 2013 at 15:32

krishwader

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