Debugging and Performance Optimization

Topic Outline (30-min)

1. Debugging Node.js Using Built-in Tools and Third-party Libraries:

   • Built-in tools:

     • console.log(): Quick debugging for inspecting variables and flow.

     • debugger: Pauses execution for inspection.

   • Third-party libraries:

     • debug: Scoped logging.

     • nodemon: Automatically restarts the server during development.

2. Identifying Common Performance Bottlenecks:

   • Examples:

     • Blocking code in the event loop.

     • Excessive synchronous operations.

     • Memory leaks caused by closures or unhandled resources.

3. Optimizing the Event Loop and Memory Usage:

   • Avoid long-running tasks in the main thread.

   • Use asynchronous APIs (e.g., fs.readFile instead of fs.readFileSync).

   • Garbage collection tips:

     • Remove unused variables.

     • Avoid circular references.

4. Profiling Applications and Reading Performance Metrics:

   • Tools:

     • Built-in --inspect flag to profile with Chrome DevTools.

     • clinic.js for automated performance profiling.

   • Steps:

     • Generate a flamegraph to identify slow functions.