Backbone.Collection.prototype.getOrCreate

get-or-create.js

Backbone.Collection.prototype.getOrCreate = function(model, options) {
  var _model;

  // Ensure model has an id property and attempt to get out of the collection
  if (model.id && _model = this.get(model.id)) {
    options && options.success(_model);

    return _model;
  }

  // Model doesn't exist, create
  return Backbone.Collection.prototype.create.call(this, model, options);
};

// USAGE

var C = Backbone.Collection.extend({});
var c = new C;

var model = c.getOrCreate({ id: 5 }, {
  success: function(model) {
    console.log(model);
  }
});