what is passport.initialize()? (nodejs express)

Question

I'm now trying to apply passport module in my apps.

I'm reading some manuals, and there say,

app.use(passport.initialize());
app.use(passport.session());

what is app.use(passport.initialize()) exactly doing?

passport.session() is maybe for the passport to use the session information,

But I have no idea about the passport.initialize()

Answer 1

passport.initialize() is a middle-ware that initialises Passport.

Middlewares are functions that have access to the request object (req), the response object (res), and the next middleware function in the application’s request-response cycle.

Passport is an authentication middleware for Node that authenticates requests.

So basically passport.initialize() initialises the authentication module.

passport.session() is another middleware that alters the request object and change the 'user' value that is currently the session id (from the client cookie) into the true deserialized user object. It is explained in detail here.