res.type(mime.lookup(path)) -> res is a type of express.Response
res.setHeader('Content-Type', mime.lookup(path))
Can I know are above two lines the same?
You can test by calling api from client or using log on server, check more View Express JS response headers?
Yes it has same functionality to set Content-Type
to response header.
Here documentation for res.type
https://expressjs.com/en/api.html#res.type
And here documentation for res.set