What's the best way to query an array in javascript to get just the items from it I want?

Question

I have an array like this (with just over 3000 objects instead of the 3 here):

items = [{name:\'charlie\', age:\'16\'}, {name:\'ben\', age:\'18\'}, {name:\'s         


        

Answer 1

If you're going to do the search often it may be best to keep a version of your data in a form that is quick to access. I've used underscore.js (http://documentcloud.github.com/underscore/) to make it easy for myself, but this code here will create an object that holds your data indexed by the age field.

You end up with something that looks like this:

{
    "16": [
        {
            "name": "charlie",
            "age": "16"
        }
    ],
    "18": [
        {
            "name": "ben",
            "age": "18"
        },
        {
            "name": "steve",
            "age": "18"
        }
    ]
}

The code:

var itemsByAge = _(items).reduce(function(memo, item) {
    memo[item.age] = memo[item.age] || [];
    memo[item.age].push(item);
    return memo;
}, {});

alert(JSON.stringify(itemsByAge["18"]));