Question

var set = [{"color":"blue"},{"color":"green"},{"color":"red"},{"color":"green"}];

I’d like to be able to do something like a db call, set.find({"color":"green"}) and have it return an array full of objects that contain that property.

Answer 1

Using Array#filter, for this particular case the code would look like

var results = set.filter(function (entry) { return entry.color === "green"; });

Array#filter is not implemented in some older browsers, so see the linked article for a backward compatibility shim, or better yet get a full-fledged ES5 shim.

For the more general case, it’s just a matter of extending this idea:

function findByMatchingProperties(set, properties) {
    return set.filter(function (entry) {
        return Object.keys(properties).every(function (key) {
            return entry[key] === properties[key];
        });
    });
}

var results = findByMatchingProperties(set, { color: "green" });

Again, I am using ECMAScript 5 methods Object.keys and Array#every, so use an ES5 shim. (The code is doable without an ES5 shim but uses manual loops and is much less fun to write and read.)