MCQs on Error Handling and Debugging Best Practices | JavaScript Advanced

Mastering Error Handling and Debugging Best Practices is essential for modern developers. Explore topics like advanced error handling, debugging asynchronous code, error tracking, logging, and leveraging source maps for seamless debugging.

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Advanced Error Handling Techniques

1. Which of the following is an example of a try-catch block?
   A. function test() { return true; }
   B. try { console.log(x); } catch(e) { console.error(e); }
   C. const handleError = (error) => console.log(error);
   D. throw new Error("Error occurred!");
2. Why is it important to use custom error classes?
   A. To simplify code
   B. To track specific errors and their origins
   C. To reduce code complexity
   D. To handle asynchronous errors
3. What does the finally block in a try-catch-finally construct do?
   A. Executes only if no error occurs
   B. Executes always, regardless of error presence
   C. Logs the error details
   D. Stops the error propagation
4. What is the primary purpose of the throw statement?
   A. To log messages
   B. To reassign variables
   C. To manually generate exceptions
   D. To handle null values
5. Which keyword is commonly used for defining a synchronous error handler?
   A. await
   B. try
   C. resolve
   D. catch

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Debugging Asynchronous Code

6. What challenge does asynchronous code introduce in debugging?
   A. Complex syntax
   B. Errors occurring out of sequence
   C. Simplified error tracking
   D. Excessive memory usage
7. Which method is best suited for handling rejected promises?
   A. promise.catch()
   B. promise.finally()
   C. promise.resolve()
   D. promise.all()
8. What does the async keyword indicate in a function declaration?
   A. The function will run synchronously
   B. The function always throws an error
   C. The function returns a promise
   D. The function is non-returnable
9. How can you ensure exceptions in an async/await block are handled?
   A. Using a finally block
   B. Wrapping the block in try-catch
   C. Calling resolve()
   D. Avoiding await statements
10. What debugging feature helps trace asynchronous execution paths?
    A. Execution stack
    B. Promise chaining
    C. Async hooks
    D. Function closures

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Error Tracking and Logging

11. What is the main advantage of implementing centralized logging?
    A. Increases performance
    B. Provides a single source for debugging insights
    C. Reduces code dependencies
    D. Avoids exception handling
12. What is a log level used for in error tracking?
    A. To classify log statements by severity
    B. To reset all errors
    C. To ensure synchronous logging
    D. To group logs alphabetically
13. Which log level represents critical system failures?
    A. info
    B. debug
    C. error
    D. warn
14. What is the primary role of a log aggregator?
    A. To prevent errors
    B. To store logs centrally for analysis
    C. To fix syntax issues
    D. To suppress all errors
15. Which tool is commonly used for error tracking in production environments?
    A. MongoDB
    B. Sentry
    C. React DevTools
    D. npm

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Using Source Maps in Debugging

16. What is the primary purpose of a source map?
    A. To optimize code execution speed
    B. To map minified code to original source files
    C. To prevent exceptions in production
    D. To bundle JavaScript files
17. Which tool is commonly used for generating source maps?
    A. Babel
    B. ESLint
    C. Prettier
    D. Parcel
18. How do source maps benefit developers during debugging?
    A. By preventing runtime errors
    B. By enabling them to view original code during execution
    C. By ensuring strict mode compliance
    D. By removing error stack traces
19. What file extension is typically associated with source maps?
    A. .js
    B. .json
    C. .map
    D. .css
20. How can source maps be disabled in a production environment?
    A. By using the disableMap() method
    B. By setting a configuration flag in the build tool
    C. By enabling strict mode
    D. By renaming the source files

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Miscellaneous

21. What is the purpose of stack traces in error handling?
    A. To identify code styles
    B. To locate the source of errors
    C. To avoid performance issues
    D. To map logs to servers
22. Why should sensitive information be avoided in log statements?
    A. To reduce file size
    B. To prevent security vulnerabilities
    C. To avoid clutter in logs
    D. To minimize coding effort
23. What is the role of environment-specific logging configurations?
    A. To ensure logging consistency across all environments
    B. To reduce logging overhead in production
    C. To eliminate syntax errors
    D. To maintain static code analysis
24. How does real-time monitoring complement error logging?
    A. By eliminating the need for logs
    B. By detecting issues as they occur
    C. By debugging asynchronous code
    D. By reducing log file size
25. Which of these is an effective error prevention technique?
    A. Ignoring unused errors
    B. Writing detailed tests
    C. Removing console logs
    D. Increasing stack trace size
26. What is the importance of structured logging?
    A. To improve readability and queryability of log data
    B. To reduce file size
    C. To simplify code execution
    D. To prevent error occurrences
27. Which debugging method is often avoided due to its blocking nature?
    A. Console logging
    B. Using debugger breakpoints
    C. Code linting
    D. Writing async functions
28. What is the advantage of using third-party logging libraries?
    A. Reduced dependency size
    B. Enhanced customization and integration features
    C. Faster code execution
    D. Simplified stack traces
29. What is a common mistake when using error-handling middleware?
    A. Catching errors too broadly
    B. Logging errors to multiple destinations
    C. Specifying multiple log levels
    D. Using try-catch with synchronous code
30. Which of the following improves debugging efficiency?
    A. Ignoring asynchronous exceptions
    B. Regularly reviewing logs and stack traces
    C. Minimizing error messages
    D. Removing error handlers

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Answers

Qno	Answer
1	B. try { console.log(x); } catch(e) { console.error(e); }
2	B. To track specific errors and their origins
3	B. Executes always, regardless of error presence
4	C. To manually generate exceptions
5	D. catch
6	B. Errors occurring out of sequence
7	A. promise.catch()
8	C. The function returns a promise
9	B. Wrapping the block in try-catch
10	C. Async hooks
11	B. Provides a single source for debugging insights
12	A. To classify log statements by severity
13	C. error
14	B. To store logs centrally for analysis
15	B. Sentry
16	B. To map minified code to original source files
17	A. Babel
18	B. By enabling them to view original code during execution
19	C. .map
20	B. By setting a configuration flag in the build tool
21	B. To locate the source of errors
22	B. To prevent security vulnerabilities
23	B. To reduce logging overhead in production
24	B. By detecting issues as they occur
25	B. Writing detailed tests
26	A. To improve readability and queryability of log data
27	B. Using debugger breakpoints
28	B. Enhanced customization and integration features
29	A. Catching errors too broadly
30	B. Regularly reviewing logs and stack traces