What should the return type be for a Typescript node express controller?

Question

What should the return type be for a Typescript node express controller?

What type of return function should I use in Node Express? I have come across information suggesting that I can use either any or void. However, using void is not recommended in this case. Can anyone provide some suggestions on the best approach? Currently, I am considering using

Promise<Response<any>>

, although it requires me to disable the rule "@typescript-eslint/no-explicit-any", which I am hesitant to do.

                                                     //Here: Promise<Response<any>> 
export default async function registration(req: TreqBodyReg, res: Response) {
  try {
    const { email, password } = req.body;
    const candidate = await ModelUser.findOne({ email }) as TreqBodyReg;
    if (candidate) {
      return res.status(400).json({ message: `There is already a user with the email ${email}` });
    }
    const hashPassword = bcrypt.hashSync(password, 7);
    const user = new ModelUser({ email, password: hashPassword });
    await user.save();
    return res.status(200).json({ message: `The user with the email ${email} has been successfully registered` });
  } catch (err) {
    console.log(err);
    // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
    return res.status(400).json({ message: `An error occurred during registration: ${err}` });
  }
};

typescript express

Answer 1

Answer №1

It's not necessary for Express to expect a return value from the middleware/routing function. Therefore, in your case where you're using an async function, Promise<void> would be appropriate:

export default async function registration(req: TreqBodyReg, res: Response): Promise<void> {

Some developers prefer to use return along with the last action they performed, just like you did here:

return res.status(400).json({ message: `There is user with email ${email}` });

According to the Express documentation, there isn't a specified return value for json, so it likely results in undefined. However, since many Express methods are chainable, it might return the Response object. In that case, you could split the lines like this:

res.status(400).json({ message: `There is user with email ${email}` });
return;

Answer 2

It's not necessary for Express to expect a return value from the middleware/routing function. Therefore, in your case where you're using an async function, Promise<void> would be appropriate:

export default async function registration(req: TreqBodyReg, res: Response): Promise<void> {

Some developers prefer to use return along with the last action they performed, just like you did here:

return res.status(400).json({ message: `There is user with email ${email}` });

According to the Express documentation, there isn't a specified return value for json, so it likely results in undefined. However, since many Express methods are chainable, it might return the Response object. In that case, you could split the lines like this:

res.status(400).json({ message: `There is user with email ${email}` });
return;

Answer 3

Answer №2

A different approach was taken with this code

export default async function userRegistration(req: TreqBodyReg, res: Response): Promise<Response<void>> {
  try {
    const { email, password } = req.body;
    const existingUser = await ModelUser.findOne({ email }) as TreqBodyReg;
    if (existingUser) {
      res.status(400).json({ message: `User with email ${email} already exists` });
      return;
    }
    const hashedPassword = bcrypt.hashSync(password, 7);
    const newUser = new ModelUser({ email, password: hashedPassword });
    await newUser.save();
    res.status(200).json({ message: `User with email ${email} successfully registered` });
  } catch (error) {
    console.log(error);
    // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
    res.status(400).json({ message: `Error during registration: ${error}` });
  }
};

Answer 4

A different approach was taken with this code

export default async function userRegistration(req: TreqBodyReg, res: Response): Promise<Response<void>> {
  try {
    const { email, password } = req.body;
    const existingUser = await ModelUser.findOne({ email }) as TreqBodyReg;
    if (existingUser) {
      res.status(400).json({ message: `User with email ${email} already exists` });
      return;
    }
    const hashedPassword = bcrypt.hashSync(password, 7);
    const newUser = new ModelUser({ email, password: hashedPassword });
    await newUser.save();
    res.status(200).json({ message: `User with email ${email} successfully registered` });
  } catch (error) {
    console.log(error);
    // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
    res.status(400).json({ message: `Error during registration: ${error}` });
  }
};

What should the return type be for a Typescript node express controller?

Answer №1

Answer №2

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