Backbone.js collection.unshift()

The Backbone.js collection unshift method is used to add specified model at the beginning of a collection. It takes the same options as add() method.

Syntax:

Parameter explanation:

models: It specifies the names of the collection instances, which is to be added at the beginning of a collection.

options: It contains model types and adds them to the collection instance.

See this example:

<!DOCTYPE html>
   <head>
      <title>Unshift Collection Example</title>
         <script src="https://code.jquery.com/jquery-2.1.3.min.js" type="text/javascript"></script>
         <script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.2/underscore-min.js" type="text/javascript"></script>
         <script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.1.2/backbone-min.js" type="text/javascript"></script>
   </head>
   <body>
      <script type="text/javascript">
          //'Player' is a model and contains defualt values for the model
          var Player = Backbone.Model.extend({
            defaults: {
               name: 'Sachin',
               country: 'India'
             }
          });

          //'Players' is an instance of the collection
          var Players = Backbone.Collection.extend({
	         model: Player  //model 'Player' is specified by using model property
          });

          //Here, instantiating models along with "new" keyword and store them in the collection instance
          var player1 = new Player({ id: 1, name: 'Sehwag', country: 'India'});
          var player2 = new Player({ id: 2, name: 'Dravid', country: 'India'});
          var teamArray = [player1, player2];

          //The unshift() method adds the 'player2' model to the beginning of the collection
          teamArray.unshift(player2);

          //Instantiate new collection by passing in an array of models
          var players = new Players(teamArray);
          document.write(JSON.stringify(players));
      </script>
   </body>
</html>

Test it Now

Output:

Save the above code in unshift.html file and open this file in a new browser.