auth-controller.js

const user = require('../models/user')
var config = require('../config/keys')
const jwt = require('jsonwebtoken')
const passport = require('passport');

module.exports.signup = function(req,res){

  var newUser = new user({
    email: req.body.email,
    username: req.body.username,
    password: req.body.password,
  });

  newUser.save(function(err,user) {
      if (err) {
          if (err.code === 11000) {
              return res.json({success: false,  msg: 'Username already exists.'});
          }else{
              return res.json({success: false,  msg: 'Signup failed'});
          }
      }else{
          var token = jwt.sign(user.toObject(), config.secret);
          res.json({success: true, token:'JWT ' + token, msg: 'Successful created new user.'});
          }
    });
  }


module.exports.signin = function(req,res){
  user.findOne({
    email: req.body.email
  }, function(err, user) {
    if (err) throw err;
    if (!user) {
      res.send({success: false, msg: 'Authentication failed. User not found.'});
    } else {

      user.comparePassword(req.body.password, function (err, isMatch) {
        if (isMatch && !err) {
           var token = jwt.sign(user.toObject(), config.secret);
          res.json({success: true,token:'JWT ' + token,user : user});
        } else {
          res.send({success: false, msg: 'Authentication failed. Wrong password.'});
        }
      });
    }
  });
}