if (!this._passport) { throw new Error('passport.initialize() middleware not in use'); } ^ Error: passport.initialize() middleware not in use code example

Example: passport.initialize() middleware not in use

its because you have declared the middleware after you have intialised the routes 
in the index file
the correct order is
app.use(passport.initialize());
app.use(passport.session());
app.use(passport.setAuthenticatedUser);


app.use('/', require('./routes'));