In this chapter, we will cover the following recipes:

• Routing in ExpressJS
• Modular route handlers
• Writing middleware functions
• Writing configurable middleware functions
• Writing router-level middleware functions
• Writing error-handler middleware functions
• Using ExpressJS' built-in middleware function to serve static assets
• Parsing the HTTP request body
• Compressing HTTP responses
• Using an HTTP request logger
• Managing and creating virtual domains
• Securing an ExpressJS web application with helmet
• Using template engines
• Debugging your ExpressJS web application