Proper way to sort a backbone.js collection on the fly

Question

I can successfully do this:

App.SomeCollection = Backbone.Collection.extend({
  comparator: function( collection ){
    return( collection.get( \'lastName\' ) );         


        

Answer 1

This is an old question but I recently had a similar need (sort a collection based on criteria to be supplied by a user click event) and thought I'd share my solution for others tackling this issue. Requires no hardcoded model.get('attribute').

I basically used Dave Newton's approach to extending native JavaScript arrays, and tailored it to Backbone:

MyCollection = Backbone.Collection.extend({

    // Custom sorting function.
    sortCollection : function(criteria) {

        // Set your comparator function, pass the criteria.
        this.comparator = this.criteriaComparator(criteria);
        this.sort();
    },

    criteriaComparator : function(criteria, overloadParam) {

        return function(a, b) {
            var aSortVal = a.get(criteria);
            var bSortVal = b.get(criteria);

            // Whatever your sorting criteria.
            if (aSortVal < bSortVal) {
                return -1;
            }

            if (aSortVal > bSortVal) {
                return 1;
            }

            else {
                return 0;
            }

        };
    } 

});

Note the "overloadParam". Per the documentation, Backbone uses Underscore's "sortBy" if your comparator function has a single param, and a native JS-style sort if it has two params. We need the latter, hence the "overloadParam".