能否简化这段Passport身份验证代码？

Looking at your Passport authentication code, you’ve spotted a perfect opportunity to simplify the logic without losing any reliability. Let’s walk through why the original approach has unnecessary overhead, then review the optimized version.

Original Code #

The original implementation creates a user, then immediately fetches the same user data from the database to pass to the done() callback:

// the user was not found
// create the user, get the user, and return the user object
function createUser (done, profile) {
  let props = obtainProps(profile);
  DBM.createUser(props).then(() => {
    DBM.getUser(props.id_google).then((res) => {
      return done(null, res[0]);
    }).catch( error => {
      return done(error, null);
    });
  });
}

Why This Is Redundant #

The original author probably added the post-creation fetch to "confirm" the save worked, but this step is unnecessary:

• If DBM.createUser(props) resolves successfully, we already know the user data was persisted correctly—any failures would be caught in the .catch() block.
• The props object already holds all the data we just saved to the database. There’s no value in retrieving it again.

Optimized Code #

We can remove the extra getUser call entirely and return the props object directly once the creation succeeds:

// the user was not found
// create the user then return props
function createUser (done, profile) {
  let props = obtainProps(profile);
  DBM.createUser(props).then(() => {
    return done(null, props);
  }).catch( error => {
    return done(error, null);
  });
}

Key Advantages #

• Less database overhead: One fewer round trip to the database for every new user creation.
• Simpler, cleaner code: The logic is more straightforward and easier to debug or modify later.
• No loss of reliability: We still handle errors properly, and we’re passing along the exact data that was confirmed to be saved.

内容的提问来源于stack exchange，提问作者user9723618