Question

How do I get an item from a JavaScript object:

var items = [
  {
    ITEM:1,
    AMOUNT:10
  },
  {
    ITEM:2,
    AMOUNT:20
  }
];

I want to be able to do something like this:

$(items).filter(ITEM == 1).AMOUNT;

… which would return 10.

Answer 1

You can use the Array filter method, which returns a new array containing all matching elements. (there could be more than one matching item)

var results = items.filter(function(obj) { return obj.ITEM == 1; });
for (var i = 0; i < results.length; i++)
  alert(results[i].AMOUNT);

Note that IE6 (I’m not sure about newer versions) doesn’t support the filter method. You could always define it yourself if it doesn’t exist:

if (typeof Array.prototype.filter == 'undefined')
  Array.prototype.filter = function(callback) {
    var result = [];
    for (var i = 0; i < this.length; i++)
      if (callback(this[i]))
        result.push(this[i]);
    return result;
  }