How to send data to a file that reads the 'data' event from process.stdin.on?

Question

Node.js

Here is the code for one of the hackerrank tasks on node.js:

'use strict';

const fs = require('fs');

process.stdin.resume();
process.stdin.setEncoding('utf-8');

let inputString = '';
let currentLine = 0;

process.stdin.on('data', inputStdin => {
    inputString += inputStdin;
});

process.stdin.on('end', function() {
    inputString = inputString.replace(/\s*$/, '')
        .split('\n')
        .map(str => str.replace(/\s*$/, ''));
    main();
});

function readLine() {
    return inputString[currentLine++];
}

// Complete the minimumSwaps function below.
function minimumSwaps(arr) {
}

function main() {
    const ws = fs.createWriteStream(process.env.OUTPUT_PATH);

    const n = parseInt(readLine(), 10);

    const arr = readLine().split(' ').map(arrTemp => parseInt(arrTemp, 10));

    const res = minimumSwaps(arr);

    ws.write(res + '\n');

    ws.end();
}

The question is related to this part:

process.stdin.on('data', inputStdin => {
    inputString += inputStdin;
});

process.stdin.on('end', function() {
    inputString = inputString.replace(/\s*$/, '')
        .split('\n')
        .map(str => str.replace(/\s*$/, ''));
    main();
});

How should the data be sent, in this case an array, so that the code above, written to a separate file (as I understand it, when sent, it is written to a separate file), can process these events and run the main function as a result? Thank you.