req.flash is not a function

When I configure my login route as following:

router.post('/login', passport.authenticate('local', {
    successRedirect: '/user/logout',
    failureRedirect: '/user/login?wrong',
    failureFlash: true
}));

I got a req.flash is not a function error. And indeed, req.flash is undefined.

PS: don’t take care about URL, it’s just for testing purposes. 😉

[cymen]

I adapted the above to Koa 2:

app.use(function(ctx, next) {
  ctx.flash = function(type, msg) {
    ctx.session.flash = { type: type, message: msg };
  }

  return next();
});

[DJviolin]

I managed to separate flash messages into cookies and exposing under ctx.flash. I used the example boilerplate from my previous post. Because passport.js targeting ctx.session.flash by default, you have to write your own authentication redirects in your router:

// Passport.js custom callback
// Official implementation is here:
// http://passportjs.org/docs#custom-callback
router.post('/auth', async (ctx, next) => {
  await passport.authenticate('local', (err, user, info) => {
    //console.log(`${err}\n${JSON.stringify(user, null, 4)}\n${info}`);
    if (err) { return next(err); }
    if (!user) {
      ctx.flash = {
        type: 'error',
        message: 'Login error!',
      };
      return ctx.redirect('/login');
    }
    ctx.login(user, () => {
      if (err) { return next(err); }
      ctx.flash = {
        type: 'success',
        message: 'Login was succesful!',
      };
      return ctx.redirect('/admin');
    });
  })(ctx, next);
});

This stores a json cookie in a similar object what passport creating by default. The cookies is always deleted after 10 seconds or on the next request. 10 second is defined in the linked implementation, meaning if a request takes longer, than the user can miss the flash, but you can define longer period.