trying to create a duplicate username throws an unhandled promise rejection warning (error is not handled properly)

[rooberrydev]

week7-hihi/handlers/users-handler.js

Lines 21 to 36 in 68325ba

	function addUserHandler(req, res, next) {
	let password = req.body.password;
	bcrypt
	.genSalt(10)
	.then((salt) => bcrypt.hash(password, salt))
	.then((hash) => {
	usersModel
	.addUser(req.body.username, hash, req.body.cohort)
	.then((newUser) => {
	const payload = { newUser: newUser.id };
	newUser.access_token = jwt.sign(payload, SECRET, { expiresIn: "1h" });
	res.status(201).send(newUser);
	});
	})
	.catch(next);
	}

Line 35, the .catch() is catching errors on bcrypt stuff.
but there's another promise chain that is started once hashing is complete, and this is the database insert request - usersModel.addUser.

This does error when you try and create a username that already exists (because you have the UNIQUE keyword on the username table in the database) causing the app to crash due to an unhandled promise rejection.

week7-hihi/model/users-model.js

Lines 26 to 33 in 68325ba

	function addUser(username, password, cohort) {
	return db
	.query(
	`INSERT INTO users (username, password, cohort)VALUES($1, $2, $3);`,
	[username, password, cohort]
	)
	.then((res) => res.rows);
	}

addUser, if it were to fail, would return a rejected promise with the error as the value.
and then on the other side (back in the addUserHandler), you can add a .catch() to pass on this error to the error handler middleware.

function addUserHandler(req, res, next) {
  let password = req.body.password;
  bcrypt
    .genSalt(10)
    .then((salt) => bcrypt.hash(password, salt))
    .then((hash) => {
      usersModel
        .addUser(req.body.username, hash, req.body.cohort)
        .then((newUser) => {
          console.log(newUser);
          const payload = { newUser: newUser.id };
          newUser.access_token = jwt.sign(payload, SECRET, { expiresIn: "1h" });
          res.status(201).send(newUser);
        })
        .catch(next);
    })
    .catch(next);
}

notice the two .catch(), one for the bcrypt promise chain and one for the database query promise chain.

TL:DR,

week7-hihi/handlers/users-handler.js

Lines 27 to 28 in 68325ba

	usersModel
	.addUser(req.body.username, hash, req.body.cohort)

you have an uncaught promise exception which can be fixed by adding a .catch(next) to usersModel.addUser