why am i getting ~ no response on stdout ~ in hacker rank nodejs

Question

Please who know how to run a function with stdin and stdout on hackerrank for example

function getPrimes(n){

nextPrime:
for (let i = 2; i <= n; i++) { // for each i...

  for (let j = 2; j < i; j++) { // look for a divisor..
    if (i % j == 0) continue nextPrime; // not a prime, go next i
  }

 console.log(i) ; // a prime
}
}

then use process. stdin and stdout dunction to display result

Answer 1

Hackerrank documentations haven't mentioned this.

This is how it worked for me.

// It will work on Javscript(nodejs), not sure about others
fs.createWriteStream(process.env.OUTPUT_PATH).write("Your Output");

Answer 2

Look at how the function you're writing is being used. For example, with getPrimes, look for other uses of getPrimes in the HackerRank built-in code. For example, from the sample test, there is a question asking me to complete a findNumber function:

'use strict';

const fs = require('fs');

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

let inputString = '';
let currentLine = 0;

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

process.stdin.on('end', function() {
    inputString = inputString.split('\n');

    main();
});

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



// Complete the findNumber function below.
function findNumber(arr, k) {

}

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

    const arrCount = parseInt(readLine().trim(), 10);

    let arr = [];

    for (let i = 0; i < arrCount; i++) {
        const arrItem = parseInt(readLine().trim(), 10);
        arr.push(arrItem);
    }

    const k = parseInt(readLine().trim(), 10);

    const res = findNumber(arr, k);

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

    ws.end();
}

The function findNumber is being called in the line

const res = findNumber(arr, k);

with its return value assigned to res. If the called function's return value is used, you should probably always return a value. Otherwise, if it's not being used, eg if the line was just

findNumber(arr, k);

then the return value is ignored, so your output will probably be determined by what you call console.log with.

In your case, you should probably return a value from getPrimes so that HR can parse it. Not sure what the challenge is asking for, but maybe something like

function getPrimes(n) {
  const arrOfPrimes = [];
  nextPrime: for (let i = 2; i <= n; i++) { // for each i...

    for (let j = 2; j < i; j++) { // look for a divisor..
      if (i % j == 0) continue nextPrime; // not a prime, go next i
    }

    arrOfPrimes.push(i);
  }
  return arrOfPrimes;
}

or something along those lines - just make sure something is being returned at the end, if the result of the getPrimes call is being used somewhere.