BackboneJS - Collezione At

Descrizione

Viene utilizzato per recuperare il modello da una raccolta utilizzando l'indice specificato.

Sintassi

collection.at(index)

Parametri

index - È una posizione di indice in cui potremmo ottenere il modello da una collezione.

Esempio

<!DOCTYPE html>
<html>
   <head>
      <title>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">
      
         //The model name is 'Player' and contains default values
         var Player = Backbone.Model.extend ({
            defaults: {
               id:"",
               name: ""
            }
         });

         //'PlayersCollection' is an instance of the collection
         var PlayersCollection = Backbone.Collection.extend ({
            model: Player  //model 'Player' is specified by using model property
         });
         var player1 = new Player({id:1, name: "dhoni" });
         var player2 = new Player({id:2, name: "raina"});

         //The add() method adds the models 'player1' and 'player2' to the collection instance 'mycollection'
         var mycollection = new PlayersCollection();
         mycollection.add([player1,player2]);
         document.write('<b>Players added are :</b> ' + JSON.stringify(mycollection.toJSON()));
         var player3 = new Player({id:3, name: "yuvraj" });

         //Here, adding the model 'player3' at 0th index of the collection
         mycollection.add(player3,{at:0});

         //display all the models added. player3 will be added at the 0th position
         document.write('<br><b>Now the new list of players is :</b> ' + 
            JSON.stringify(mycollection.toJSON()));
      </script>
      
   </body>
</html>

Produzione

Eseguiamo i seguenti passaggi per vedere come funziona il codice sopra:

Salva il codice sopra nel file at.htm file.
Apri questo file HTML in un browser.

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