how to compare bcrypt hash password

Question

I am new to node js, I am trying to validate a password that is encrypted, and I have given the below code which I have tried.

async function passCheck(event) {
  // in event i am passing user entered password and email
  var EnteredPassword = bcrypt.hashSync(event.password, 10); //10 saltrounds

  var fromDB = await pool.query('SELECT password from User WHERE email  = ?', event.emailID);
  if (EnteredPassword == fromDB) {
    //Here i am comparing
    console.log('valid');
  } else {
    console.log('invalid');
  }
}

Answer 1

bcrypt has a built-in method for comparing hashes.

async function passCheck(event) {
  var fromDB = await pool.query('SELECT password from User WHERE email  = ? Limit 1', event.emailID);
  // --------------------------------------------------------------------------^
  // Added limit 1 to make sure the only one record will be returned.
  if (fromDB.length > 0 && await bcrypt.compare(event.password, fromDB[0].password)) {
    //Here i am comparing
    console.log('valid');
  } else {
    console.log('invalid');
  }
}

DB result sets usually returns an array of objects, therefore, you should check that there are some results (fromDB.length > 0) and then pass to the compare method the hashed string itself.