Passport local strategy. Whole file is available https://github.com/AndrejGajdos/auth-flow-spa-node-react/blob/master/script/controllers/auth.js

auth.js

passport.use(
  new LocalStrategy(
    {
      usernameField: 'email',
      passwordField: 'password',
    },
    async (email, password, done) => {
      let user = null;
      await getAsync('usersMockDatabase').then((users) => {
        const currUsers = JSON.parse(users);
        user = currUsers.find(currUser => currUser.email === email);
      });
      if (!user) {
        done({ type: 'email', message: 'No such user found' }, false);
        return;
      }
      if (bcrypt.compareSync(password, user.password)) {
        done(null, { id: user.id, email: user.email, userName: user.userName });
      } else {
        done({ type: 'password', message: 'Passwords did not match' }, false);
      }
    },
  ),
);