shift

优质

小牛编辑

136浏览

2023-12-01

描述 (Description)

它从集合中删除第一个项目。

语法 (Syntax)

collection.shift(options)

参数 (Parameters)

options - 它包括将从集合中删除的模型类型。

例子 (Example)

<!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">
         //'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
         });
         //Instantiate the models along with "new" keyword and store them in the collection instance
         var player1 = new Player({ id: 1, name: 'gayle', country: 'west indies'});
         var player2 = new Player({ id: 2, name: 'yuvraj', country: 'india'});
         var teamArray = [player1, player2];
         document.write("<b>Before using shift method:</b>",JSON.stringify(teamArray));
         //The shift() method removes the model 'player1' from the collection
         teamArray.shift();
         //The 'players' is the collection instance and contains array of models
         var players = new Players(teamArray);
         document.write("<br><b>After using shift method:</b>",JSON.stringify(players));
      </script >
   </body>
</html>