Question

I encounter something quite strange while trying to iterate properties of an object stored
using jQuery data function.

Here is the thing (as an example) :

wrapper.data( 'infos', {
    label: $('input[name*="label"]').val(),
    amount: $('input[name*="amount"]').val(),
    etc..
});

Then i try to read values using :

$.each( wrapper.data('infos'), function(k,v) {
  console.log(k + ' > ' + v);
});

And i get a beautiful output like :

0 > undefined
1 > undefined
... 
239 > undefined

If i output this object as if, i can read properties without any difficulties.
Is it somehow related to jquery caching or something ?

Answer 1

Because your object has a length property, it is being interpeted as an array as, in 1.7.2 at least, whether it’s an array or not is determined via:

length = obj.length,            
isObj = length === undefined || jQuery.isFunction( obj );

So you should either;

1. Call your length property something else

2. Use a for / in loop instead.

   var data = wrapper.data('infos')
   
   for (var x in data) {
       if (data.hasOwnProperty(x)) { // omit properties from the prototype chain
           console.log(x + ' > ' + data[x]);
       }
   }