Filtering backbone collection on multiple attribtues

Question

Is this a good approach to filtering a backbone collection on multiple attributes:

filterData: function(params) {
    // store original data for clearing filters
    this.originalModels = this.models.slice();
    for (var key in params) {
        var val = params[key];
        // if we are dealing with multiple values in an array
        // i.e. ['ford','bmw','mazda']
        if (typeof val === "object") {
            var union = [];
            for (var k in val) {
                var subval = val[k];
                var matched = _.filter(this.models, function(house) {
                   return house.get(key) == subval; 
                });
                union = union.concat(matched);
            }
            this.models = union;
        } else {
           var results = _.filter(this.models, function(house) {
               return house.get(key) == val;
           });
           this.models = results;
        }
    } // end for
    return this.reset(this.models);
},
clearFilters: function() {
    return this.reset(this.originalModels);
}

I tested it and it allows me to filter a collection in the following manner:

filterParams = {brand:['ford','bmw','mazda'], color:black}

carCollection.filterData(filterParams);

It seems to work, but I don't know if there is a better way of doing this.

I tested the Backbone.Collection.where() method, but it does not work if I want to say brand: ['bmw','mazda','ford']

Answer 1

You should be able to use something like this:

filterData: function(params) {
    // store original data for clearing filters
    this.originalModels = this.models.slice();

    _.each(params, function(val, key){
        if (typeof val !== 'object') val = [ val ];
        this.models = _.filter(this.models, function(model){
            return _.indexOf(val, model.get(key)) !== -1;
        }, this);
    }, this);
    return this.reset(this.models);
}

Answer 2

Backbone.js collections have access to a number of underscore.js methods, including filter().

carCollection.reset(carCollection.filter(function(car){
  return $.inArray(car.brand,['ford','bmw','mazda']) && car.color === 'black';
}));

Not tested, but that should work if you use jQuery. If not, you can create your own inArray() function