Express

Question 1

How do you add express to your package dependencies?

Answer 1

npm install express

Question 2

What Express application method starts the server and binds it to a network PORT?

Answer 2

app.listen([port[, host[, backlog]]][, callback]) Binds and listens for connections on the specified host and port

Question 3

How do you mount a middleware with an Express application?

Answer 3

mount path or app.use() (app.use([path,] callback [, callback…]) and app.METHOD() (get , put, post)

Question 4

Which objects does an Express application pass to your middleware to manage the request/response lifecycle of the server?

Answer 4

req (request) ,res (respond) ,next

Question 5

What is the appropriate Content-Type header for HTTP messages that contain JSON in their bodies?

Answer 5

application/json

Question 6

What is the significance of an HTTP request’s method?

Answer 6

communication purposes

Question 7

What does the express.json() middleware do and when would you need it?

Answer 7

• It parses incoming requests with JSON payloads and is based on body-parser (A payload in API is the actual data pack that is sent with the GET method in HTTP.)
• Returns middleware that only parses JSON and only looks at requests where the Content-Type header matches the type option.
• A new body object containing the parsed data is populated on the request object after the middleware (i.e. req.body), or an empty object ({})