setuppassport.js

var passport = require("passport");
var LocalStrategy = require("passport-local").Strategy;

var User = require("./models/user");

module.exports = function(){

  passport.serializeUser(function(user, done) {
  done(null, user._id);
});

passport.deserializeUser(function(id, done) {
  User.findById(id, function (err, user) {
    done(err, user);
  });
});

passport.use("login", new LocalStrategy(function(username, password, done) {
  User.findOne({ username: username }, function(err, user) {
    if (err) { return done(err); }
    if (!user) {
      return done(null, false, { message: "No user has that username!" });
    }
    user.checkPassword(password, function(err, isMatch) {
      if (err) { return done(err); }
      if (isMatch) {
        return done(null, user);
      } else {
        return done(null, false, { message: "Invalid password." });
      }
    });
  });
}));

};