Service layer pattern in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the service layer module correctly.

Express

const userService = require('[1]');

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A./services/userService

Bexpress

Chttp

Dpath

Attempts:

3 left

💡 Hint

Common Mistakes

Importing core modules like 'express' instead of the service file.

The service layer module is usually imported from a local file path like './services/userService'.

2fill in blank

medium

Complete the code to call the service method that fetches all users.

Express

app.get('/users', async (req, res) => {
  const users = await userService.[1]();
  res.json(users);
});

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Ause

Blisten

Csend

DgetAllUsers

Attempts:

3 left

💡 Hint

Common Mistakes

Using Express app methods like 'listen' or 'use' instead of service methods.

The service layer method to fetch all users is typically named 'getAllUsers'.

3fill in blank

hard

Fix the error in the service method call to get a user by ID.

Express

const user = await userService.getUserById([1]);

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Ares.send

Breq.body

Creq.params.id

Dapp.get

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the whole request body or response methods instead of the ID.

To get a user by ID, the service method needs the ID from the request parameters: 'req.params.id'.

4fill in blank

hard

Fill both blanks to create a service method that updates a user and returns the updated user.

Express

async function updateUser([1], [2]) {
  const updatedUser = await UserModel.findByIdAndUpdate(id, data, { new: true });
  return updatedUser;
}

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Aid

Bdata

Creq

Dres

Attempts:

3 left

💡 Hint

Common Mistakes

Using request or response objects directly in service methods.

The updateUser method takes 'id' and 'data' as parameters to update the user and return the new data.

5fill in blank

hard

Fill all three blanks to create a service method that deletes a user by ID and returns a confirmation message.

Express

async function deleteUser([1]) {
  await UserModel.findByIdAndDelete([2]);
  return { message: `User with ID [3] deleted.` };
}

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Aid

C${id}

DuserId

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently or missing template literal syntax.

The deleteUser method uses 'id' as the parameter and in the delete call, and the message uses template syntax '${id}' to show the deleted user ID.