Backbone provides a single gateway for all its data communication. All the data requests are sent via the sync() method that gets called whenever any CRUD operation is processed. This sync() method does a number of jobs, such as setting the URL, parameters and content type, and mimicking HTTP requests for old browsers that do not support PUT and DELETE requests. Whenever we call a fetch() or save() method on a model or collection, the sync() method is executed.

But when do we need to override this method? Sometimes, you may need a separate implementation of the REST API method, which Backbone does not provide. This can be for a certain model or collection, or the implementation can persist for the complete project. This is how the method map is written in Backbone by default:

var methodMap = {
  'create': 'POST',
  'update': 'PUT',
  'patch': 'PATCH',
  'delete': 'DELETE',
  'read': 'GET'
};

Now, you may have a particular model or collection that will listen...