Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

const fs   = require('fs');
const path = require('path');
const zlib = require('zlib');

// Copy a large file using streams (memory-efficient):
function copyFile(src, dest) {
    const readable = fs.createReadStream(src);
    const writable = fs.createWriteStream(dest);

readable.pipe(writable);

writable.on('finish', () => console.log('Copy complete.'));
    readable.on('error', (err) => console.error('Read error:', err));
    writable.on('error', (err) => console.error('Write error:', err));
}

copyFile('big-file.txt', 'big-file-copy.txt');

// Compress a file on-the-fly with gzip:
function compressFile(src, dest) {
    const readable  = fs.createReadStream(src);
    const gzip      = zlib.createGzip();
    const writable  = fs.createWriteStream(dest);

readable.pipe(gzip).pipe(writable);

writable.on('finish', () => console.log('Compressed:', dest));
}

compressFile('big-file.txt', 'big-file.txt.gz');

// Process a CSV line-by-line using readline:
const readline = require('readline');

const rl = readline.createInterface({
    input: fs.createReadStream('data.csv'),
});

rl.on('line', (line) => {
    const columns = line.split(',');
    console.log(columns[0]); // Print first column
});

rl.on('close', () => console.log('Done reading CSV.'));