Student Activity

Student Activity (30-min)

Step-by-Step Procedure

1. Implement a Simple Callback Function for Reading a File (15 min):

   • Create a file named callbackExample.js.

   • Add the following code:

     javascript코드 복사const fs = require('fs');
     
     const readFile = (filePath, callback) => {
       fs.readFile(filePath, 'utf8', (err, data) => {
         if (err) return callback(err);
         callback(null, data);
       });
     };
     
     readFile('example.txt', (err, data) => {
       if (err) {
         console.error('Error reading file:', err.message);
       } else {
         console.log('File content:', data);
       }
     });

   • Create a text file example.txt with some sample content: "Hello, Node.js!"

   • Run the script:

     bash코드 복사node callbackExample.js

2. Convert the Callback Function into a Promise-Based Function (15 min):

   • Modify the above code into a new file named promiseExample.js:

     javascript코드 복사const fs = require('fs').promises;
     
     const readFile = (filePath) => {
       return fs.readFile(filePath, 'utf8');
     };
     
     readFile('example.txt')
       .then((data) => console.log('File content:', data))
       .catch((err) => console.error('Error reading file:', err.message));

   • Run the script:

     bash코드 복사node promiseExample.js