primes

primes.js

const fs = require("fs");
var i = 0;
var goto = 10000 + 1;
//see if primes.txt exists if it does, delete it
if (fs.existsSync("primes.txt")) {
  fs.unlinkSync("primes.txt");
}
//same for notprimes.txt
if (fs.existsSync("notprimes.txt")) {
  fs.unlinkSync("notprimes.txt");
}

while (true) {
  if (i != goto) {
    if (isPrime(i)) {
      console.log(`${i.toString()} is prime out of ${goto - 1} numbers` );
      //append this to a file
      fs.appendFileSync("primes.txt", `${i.toString()}\n`);
    } else {
      console.log(
        `${i.toString()} is not prime out of ${goto - 1} numbers` 
      );
      fs.appendFileSync("notprimes.txt", `${i.toString()}\n`);
    }
    i++;
  } else {
    if (i > goto) {
      exit(0);
      break;
    }
  }
}

function isPrime(num) {
  for (var i = 2; i < num; i++) {
    if (num % i === 0) {
      return false;
    }
  }
  return num > 1;
}