Edit the final part of large(1.5gb) text file in NodeJS

Additional solution for updating large-sized files with Transform as you wanted but working slower than Milos's code for my specific situation,

const fs = require('graceful-fs');
const { Transform } = require('stream');

const sourceFilePath = 'jsfiles.txt';
const destinationFilePath = 'new.txt';

// Create a transform stream to modify the data
const transformStream = new Transform({
    transform(chunk, encoding, callback) {
        // Modify the data as needed
        var modifiedData = chunk.toString().slice(0, -1); // remove last comma
        this.push(`${modifiedData}]`); // add last closing bracket
        callback();
    }
});

// Create a readable stream from the source file
const readStream = fs.createReadStream(sourceFilePath, { encoding: 'utf8' });

// Create a writable stream to the destination file
const writeStream = fs.createWriteStream(destinationFilePath, { encoding: 'utf8' });

// Pipe the data through the transform stream before writing to the destination file
readStream.pipe(transformStream).pipe(writeStream);

// Handle events when the copying is complete
readStream.on('end', () => {
    console.log('File duplication completed.');
});

writeStream.on('finish', () => {
    console.log('Data has been written to the destination file.');
});

// Handle errors during the process
readStream.on('error', (err) => {
    console.error('Error reading from the source file:', err.message);
});

transformStream.on('error', (err) => {
    console.error('Error transforming data:', err.message);
});