Backbone.js collection.sync()

It is used to maintain the state of a collection to the server. It can be overridden for custom behavior.

Syntax:

Parameter explanation:

method: It represents the CRUD operations: create, read, update and delete.

collection: It contains set of models to save the data in the collection.

options: It is used to display success or error message depending on the method succeeded.

Let's take an example.

See this example:

 <!DOCTYPE html>
   <head>
      <title>Sync 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 sync() method reads and fetches the model data
         Backbone.sync = function(method, model) {
            document.write("The state of the model is:");
            document.write("<br>");

            //The 'method' specifies state of the model
            document.write(method + ": " + JSON.stringify(model));
         };

         //The 'myval' is collection instance and contains the values which are to be fetched in the collection
         var myval = new Backbone.Collection({
            site:"JavaTpoint",
            title:"A solution of all technology"
         });

         //The myval.fetch() method display the model's state by delegating the sync() method
         myval.fetch();
         </script>
         </body>
      </html>

Test it Now

Output:

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