Question

I have a collection with models that all have an array of tags.

If I wanted to grab a model that had one tag I would do like so:

models.filter(function(x) {
    return _.contains(x.get("tags"), 'google');
});

This would grab the models that have the tag google. The problem I am having is that I cant put more that one tag there, I need for it to be an array. How would I go about grabbing all the models that have multiple tags (ex: google, yahoo, apple)? The contains method only supports 1 string and not an array

Answer 1

You could use _.intersection thusly:

var want_all = ['google', 'yahoo', 'apple'];
models.filter(function(m) {
    return _.intersection(m.get('tags'), want_all).length == want_all.length;
});

The _.intersection(a, b) will give you an array with all the elements that are common to both a and b, if the intersection is the same size as the array/set you’re looking for then m.get('tags') has everything you’re looking for.