Question

I think the title explains it well enough. I’ve got an array that has two values per object and I need to look up the object by one of those values then assign a third to it.

Here are the guts:

$slides.push({
    img: el.attr('href'),
    desc: el.attr('title').split('Photo #')[1]
});

Which builds an array as such:

Object
    desc: 127
    img: img/aaron1.jpg
Object
    desc: 128
    img: img/aaron2.jpg

I’d like to look up the desc value, then assign a third value of in: yes

$slides.findInArray('desc', '127').addValueToObject('in','yes')

Answer 1

http://jsfiddle.net/S3cpa/

var test = [
    {
        desc: 127,
        img: 'img/aaron1.jpg',
    },
    {
        desc: 128,
        img: 'img/aaron2.jpg',
    }
];

function getObjWhenPropertyEquals(prop, val)
{
    for (var i = 0, l = test.length; i < l; i++) {
        // check the obj has the property before comparing it
        if (typeof test[i][prop] === 'undefined') continue;

        // if the obj property equals our test value, return the obj
        if (test[i][prop] === val) return test[i];
    }

    // didn't find an object with the property
    return false;
}

// look up the obj and save it
var obj = getObjWhenPropertyEquals('desc', 127);

// set the new property if obj was found
obj.in = obj && 'yes';