Compiled Learning Objectives

WebSockets

• Stream live updates from a server using WebSockets.
• Discuss the trade-offs of using WebSockets or polling.
• Describe properties of message formats (e.g. including a command name).

Adding like/dislike

• Identify what data needs to be stored and exchanged between a client and server.
• Devise a scheme for differentiating messages with different meanings (e.g. a new message vs a new like).
• Contrast giving updated values as absolute values or relative changes.
• Implement an end-to-end feature involving data updates and reconciliation across a client and server.

Different experiences for different users

• TODO

Extracting common functionality

• Identify and explain the risks and costs of duplicate code
• Extract functionality used by multiple route handlers into a common function

Extracting a middleware

• Identify and explain the risks and costs of manually calling code (e.g. authentication validators/extractors) from multiple route handlers
• Explain the middleware pattern
• Implement and wire up a middleware