Best practice for async/await in TypeScript-CodePudding

I wanted to double-check my thinking on using TypeScript in ExpressJS. Here's my abridged code in question:

/**
 * Verifies that an email address exists in the DB.
 * If so, sends them an email to recover their password.
 * 
 * @param {Request} req 
 * @param {Response} res 
 */
const sendPasswordRecoveryEmail = (req: Request, res: Response) => {
  const email = req.body.email

  const checkForEmailAddress = async (email: string) => {
    return await pool.query(`SELECT password FROM users WHERE email = $1`, [email]);
  };

  const updatePasswordFields = async (password: string, newPassword: string, email: string) => {
    return await pool.query(`UPDATE users SET last_password = $1, password = $2 WHERE email = $3`, [password, newPassword, email]);
  };

  const passwordRecoveryProcess = async (email: string) => {
    try {
      res.status(200).send({ status: true, message: 'Password recovery process initiated.' });

      const results = await checkForEmailAddress(email);
      if (results.rows.length === 1) {
        const existingPassword = results.rows[0].password;
        const newTempPassword = generateRandomPassword();
        await updatePasswordFields(existingPassword, newTempPassword, email);
        const body = `...`;
        emailService({email, subject: 'MySite Password Recovery', body});
      }
    } catch (error) {
      console.error('Error', error);
    }
  }

  passwordRecoveryProcess(email); // Initiate async Password Recovery Process
};

With this line of code:

const results = await checkForEmailAddress(email);

I'm using await before calling the function. Then within the function itself I'm also using async/await. Is this the correct practice or is there some redundancy with it?

CodePudding user response：

Nested awaits inside functions calling other async functions / Promises is completely normal, especially when you're dealing with a library or are trying to abstract away some of the logic.

That said, in this particular situation, where everything is defined inside a single relatively short function, and your extra functions are composed of only a single line and only get called once, I'm not seeing how they're helping anything. There is no repetitive logic to abstract away. You may as well do

const sendPasswordRecoveryEmail = (req: Request, res: Response) => {
  const { email } = req.body;
  try {
    res.status(200).send({ status: true, message: 'Password recovery process initiated.' });
    const emailResult = await pool.query(`SELECT password FROM users WHERE email = $1`, [email]);
    if (results.rows.length === 1) {
      const existingPassword = emailResult.rows[0].password;
      const newTempPassword = generateRandomPassword();
      await pool.query(`UPDATE users SET last_password = $1, password = $2 WHERE email = $3`, [existingPassword, newTempPassword, email]);
      const body = `...`;
      emailService({email, subject: 'MySite Password Recovery', body});
    }
  } catch (error) {
    console.error('Error', error);
  }
};

That said, what you're doing now isn't forbidden - it just looks a little bit odd (though there's no need to await a Promise you're returning immediately, if you aren't inside a try block - just return the Promise, don't await it).

But you might consider only sending a response to the user after successfully getting to the email service, something like:

const sendPasswordRecoveryEmail = (req: Request, res: Response) => {
  const { email } = req.body;
  try {
    const emailResult = await pool.query(`SELECT password FROM users WHERE email = $1`, [email]);
    if (results.rows.length !== 1) {
        res.status(401).send({ status: false, message: 'Email not found' });
        return;
    }
    const existingPassword = emailResult.rows[0].password;
    const newTempPassword = generateRandomPassword();
    await pool.query(`UPDATE users SET last_password = $1, password = $2 WHERE email = $3`, [existingPassword, newTempPassword, email]);
    const body = `...`;
    // does the below need an `await`, perhaps?
    emailService({email, subject: 'MySite Password Recovery', body});
    res.status(200).send({ status: true, message: 'Password recovery process initiated.' });
  } catch (error) {
    console.error('Error', error);
    res.status(500).send({ status: false, message: 'Unexpected server error' });
  }
};