CrowdProcess Tutorial

run.js

// a brute force prime number finder

// interval should be something like
// {"lower": 1000, "upper": 2000}

function Run (interval) {
  // we will walk through the following interval
  // to look for prime numbers:
  var lower = interval.lower;
  var upper = interval.upper;
  
  var primeNumbers = []; // we'll store them here
  
  // looping through the interval
  for (var i = lower; i < upper; i++) {
    // the isPrime function checks if a number is prime.
    // it's declared outside of the Run function, on line 26.
    if (isPrime(i))
      primeNumbers.push(i);
  }
  
  // return all the prime numbers that we found
  return primeNumbers;
}

function isPrime (i) {
  var number = i; // number to check
  var n = i // we'll iterate to all the numbers before it
  var isPrime = true; // assume it's prime, we'll try to disprove
  while (n--) {
    // every number is divisible by itself and one,
    // we don't want to divide it by zero
    if (n === 0 || n === 1 || n === number)
      continue; // continue actually means skip the rest
                // of this iteration and keep looping
  
    // if it's divisible by any other number
    if (!(number % n))
      isPrime = false; // then it's not a prime number
  }
  
  return isPrime;
}