Configure Strategy the "return" is Redundant

[JohnJiang900526]

// example 
passport.use(new LocalStrategy(
  function(username, password, done) {
    User.findOne({ username: username }, function (err, user) {
      if (err) { return done(err); }
      if (!user) { return done(null, false); }
      if (!user.verifyPassword(password)) { return done(null, false); }
      return done(null, user);
    });
  }
));

//  In fact, removing return is also effective, and adding return will also cause misunderstanding
passport.use(new LocalStrategy(
  function(username, password, done) {
    User.findOne({ username: username }, function (err, user) {
      if (err) { done(err); }
      if (!user) { done(null, false); }
      if (!user.verifyPassword(password)) { done(null, false); }
      done(null, user);
    });
  }
));

[jasonandmonte]

The return stops the evaluation of the function block. In your example done(null, user) would be called regardless if done was called from the if statements.

Example that illustrates the difference with and without the return:
https://stackoverflow.com/a/59619194/7582783