Returns the unique models from any Backbone collections passed in. Just some fun with functional programming.

getUniqueModelsFromCollections.js

var _ = require('underscore');

module.exports = function () {
    var collectionArray = _.toArray(arguments);
    return _.reduce(collectionArray, function (memo, collection) {
        return memo.concat(collection.reject(function (model) {
            return _.contains(_.pluck(memo, 'id'), model.id);
        }));
    }, []);
};