JavaScript: Backbone.Collection.move Method

gistfile1.js

/**
* Moves a model to the given index, if different from its current index. Handy
* for shuffling models about after they've been pulled into a new position via
* drag and drop.
*/
Backbone.Collection.prototype.move = function(model, toIndex) {
  var fromIndex = this.indexOf(model)
  if (fromIndex == -1) {
    throw new Error("Can't move a model that's not in the collection")
  }
  if (fromIndex !== toIndex) {
    this.models.splice(toIndex, 0, this.models.splice(fromIndex, 1)[0])
    this.trigger('move', this);
  }
}