Node read/write stream

index.js

const fs = require('fs');
const readline = require('readline');

const inputFilePath = process.argv[2]; // Change this to your desired input CSV file path
const outputFilePath = process.argv[3]; // Change this to your desired output CSV file path

const readInterface = readline.createInterface({
    input: fs.createReadStream(inputFilePath),
    output: fs.createWriteStream(outputFilePath),
    console: false,
});

let isFirstLine = true;
const outputStream = fs.createWriteStream(outputFilePath);

readInterface.on('line', (line) => {
    if (isFirstLine) {
        outputStream.write(`${line}\n`);
        isFirstLine = false;
    } else if (line.startsWith('Product')) {
        outputStream.write(`${line}\n`);
    }
});

readInterface.on('close', () => {
    outputStream.end();
    console.log('CSV processing completed.');
});