Authentication Error Class

Devise an AuthError class that extends Error to manage authentication-related errors distinct from other system errors, such as when login credentials are incorrect.

class AuthError extends Error {
  constructor(message) {
    super(message);
    this.name = 'AuthError';
    if (Error.captureStackTrace) {
      Error.captureStackTrace(this, AuthError);
    }
  }
}

Defines a new class 'AuthError' extending the native JavaScript 'Error' object. This class will be used to handle authentication-specific errors, providing a custom error name 'AuthError' for ease of debugging.

function authenticateUser(username, password) {
  // Replace this logic with real authentication mechanism
  const isLoginSuccess = false;
  if (!isLoginSuccess) {
    throw new AuthError('Invalid username or password');
  }
}

An example function 'authenticateUser' that simulates a login process. If the login fails, it throws an 'AuthError' with a message indicating that the username or password is invalid.

try {
  authenticateUser('user', 'pass');
} catch (error) {
  if (error instanceof AuthError) {
    // Handle the authentication error
    console.error('Authentication failed:', error.message);
  } else {
    // Handle other kinds of errors
    console.error('An unexpected error occurred:', error);
  }
}

Demonstrates usage of the 'authenticateUser' function within a try-catch block. If an 'AuthError' is caught, it is handled separately from other types of errors, allowing for more granular error handling specific to authentication.