// Validation rules.var loginValidate = [ check('username', 'Username Must Be an Email Address').isEmail(), check('password').isLength({ min: 8 }) .withMessage('Password Must Be at Least 8 Characters') .matches('[0-9]').withMessage('Password Must Contain a Number') .matches('[A-Z]').withMessage('Password Must Contain an Uppercase Letter')];// Process user input.app.post('/login', loginValidate, (req, res) => { // Insert Login Code Here});