MEAN Web Development - Second Edition

The application, request, and response objects

Express presents three major objects that you'll frequently use. The application object is the instance of an Express application you created in the first example and is usually used to configure your application. The request object is a wrapper of Node's HTTP request object and is used to extract information about the currently handled HTTP request. The response object is a wrapper of Node's HTTP response object and is used to set the response data and headers.

The application object

The application object contains the following methods to help you configure your application:

• app.set(name, value): This is a method used to set environment variables that Express will use in its configuration.
• app.get(name) ...