Custom error classes in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a custom error class named MyError.

Node.js

class MyError extends [1] {
  constructor(message) {
    super(message);
    this.name = 'MyError';
  }
}

Drag options to blanks, or click blank then click option'

AObject

BArray

CError

DFunction

Attempts:

3 left

💡 Hint

Common Mistakes

Extending Object or Array instead of Error.

Forgetting to call super(message) in constructor.

The custom error class should extend the built-in Error class to behave like an error.

2fill in blank

medium

Complete the code to throw a new instance of the custom error MyError with a message.

Node.js

throw new [1]('Something went wrong');

Drag options to blanks, or click blank then click option'

AError

BMyError

CTypeError

DReferenceError

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing the base Error instead of the custom error.

Forgetting the new keyword.

To throw the custom error, create a new instance of MyError.

3fill in blank

hard

Fix the error in the custom error class by completing the missing call to the parent constructor.

Node.js

class ValidationError extends Error {
  constructor(message) {
    [1];
    this.name = 'ValidationError';
  }
}

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Asuper(message)

Bthis.message = message

CError.call(this, message)

Dreturn message

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning message directly without calling super.

Calling Error.call without super in ES6 classes.

Calling super(message) ensures the base Error class is properly initialized with the message.

4fill in blank

hard

Fill both blanks to create a custom error class named DatabaseError that sets the name and captures the stack trace.

Node.js

class DatabaseError extends Error {
  constructor(message) {
    super(message);
    this.name = [1];
    if (Error.captureStackTrace) {
      Error.captureStackTrace(this, [2]);
    }
  }
}

Drag options to blanks, or click blank then click option'

A'DatabaseError'

BDatabaseError

C'Error'

DError

Attempts:

3 left

💡 Hint

Common Mistakes

Setting name to the class instead of a string.

Passing a string instead of the class to captureStackTrace.

The name property should be set to the string 'DatabaseError'. The captureStackTrace method takes the class itself as the second argument.

5fill in blank

hard

Fill all three blanks to create a custom error class ApiError that accepts a message and a status code, sets the name, and stores the status code.

Node.js

class ApiError extends Error {
  constructor(message, statusCode) {
    super([1]);
    this.name = [2];
    this.statusCode = [3];
  }
}

Drag options to blanks, or click blank then click option'

Amessage

B'ApiError'

CstatusCode

D'Error'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing statusCode to super instead of message.

Setting name to 'Error' instead of 'ApiError'.

Not storing the statusCode property.

The constructor passes message to super, sets name to 'ApiError', and stores the statusCode property.