Check if a new user is already in the database

[jamiecoe]

When a user tries to sign up, you are not checking if they are signed up already.

You could do this by querying the database first to check if the user already exists.

Eg:

databaseConnection.query(`
    SELECT CASE WHEN EXISTS(SELECT email FROM users WHERE email = $1) THEN CAST (true AS BOOLEAN) ELSE CAST (false AS BOOLEAN) END`, [email], (err, res) => {
      const doesUserAlreadyExist = res.rows[0].case
      if (err) cb(err);
      else cb(null, doesUserAlreadyExist);
    });

This is nice because the query will give you a boolean, which you can use to decide whether the user is signed up already.