Reverse Alphabetical Sort in Backbone.js

reverse_alphabetical_sort_in_backbone

// Assumption: You have a model with a name. 

  comparator: function (User) {
    if (User.get("name")) {
      var str = User.get("name");
      str = str.toLowerCase();
      str = str.split("");
      str = _.map(str, function(letter) { return String.fromCharCode(-(letter.charCodeAt(0))) });
      return str;
    };
  }

I know this is a little old @BastinRobin but if others stumble upon this, like I did, here's a little more code for clarity on the whole asc/desc bit.

Backbone.Collection.extend({
  comparator: function(a, b) {
    var direction = 1;  // Asc
    var direction = -1; // Desc
    return direction * a.get('name').localeCompare(b.get('name'));
  }
});

For additional help on localeCompare check out: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/localeCompare

My production example using @bryancallahan's suggestion:

// Presenter/Controller
function sortUsers() {
    users.sortDirection = $usersView.hasClass('asc') ? -1 : 1;  // dsc : asc
    $usersView.toggleClass('asc')
    users.sort();
}

// Collection
App.UserCollection = Backbone.Collection.extend({
    comparator: function(a, b) {
        return this.sortDirection * a.get('name').localeCompare(b.get('name'));
    }
});