Student Activity

Student Activity (30-min)

Step-by-Step Procedure

1. Debug a Sample Node.js Application with Errors and Identify Issues (15 min):

   • Step 1: Create a file buggyApp.js:

     javascript코드 복사const http = require('http');
     
     const tasks = [
       { id: 1, title: 'Task 1' },
       { id: 2, title: 'Task 2' }
     ];
     
     const server = http.createServer((req, res) => {
       if (req.url === '/tasks') {
         res.writeHead(200, { 'Content-Type': 'application/json' });
         res.end(tasks); // Bug: Not serialized as JSON
       } else {
         res.writeHead(404, { 'Content-Type': 'text/plain' });
         res.end('Not Found'); // Bug: Missing newline
       }
     });
     
     server.listen(3000, () => {
       console.log('Server is running at http://localhost:3000');
     });

   • Step 2: Run the application:

     bash코드 복사node buggyApp.js

   • Step 3: Debug issues:

     • Use console.log to check tasks serialization.

     • Replace res.end(tasks) with:

       javascript코드 복사res.end(JSON.stringify(tasks));

   • Step 4: Add a debugger statement:

     javascript코드 복사debugger;

   • Step 5: Run the application in debug mode:

     bash코드 복사node inspect buggyApp.js

   • Step 6: Open Chrome DevTools (chrome://inspect) and inspect the paused state.

2. Use a Performance Profiling Tool Like clinic.js (15 min):

   • Step 1: Install clinic globally:

     bash코드 복사npm install -g clinic

   • Step 2: Run the application with clinic:

     bash코드 복사clinic flame -- node buggyApp.js

   • Step 3: Use Postman or a browser to send multiple requests to http://localhost:3000/tasks.

   • Step 4: Analyze the flamegraph:

     • Open the generated .html report.

     • Identify bottlenecks (e.g., blocking tasks, long synchronous operations).

   • Step 5: Optimize the application by ensuring all I/O operations are asynchronous.