Experimenting with new process.prevTick() API

0-primeFactor.js

//
// Calculating prime factors in polynomial time using node.js process.prevTick()
//
// see: http://en.wikipedia.org/wiki/Prime_factor
// see: http://en.wikipedia.org/wiki/Novikov_self-consistency_principle
//
// Authors:
//   http://jesusabdullah.net/
//   http://marak.com
//

function primeFactor (n) {

  //
  // If f is not defined, initialize it to zero
  //
  if(typeof f === "undefined") {
    var f = 0;
  }

  //
  // 0 and 1 do not have prime factors
  //
  if(n === 0 || n === 1) {
    return ('no prime factors found');
  }

  //
  // Check if f is a prime factor
  //
  if(f !== n && (f % n === 0) && isPrime(f)) {

    //
    // If f is a prime factor, send f to the previous tick
    //
    process.prevTick(function(){
      //
      // Important: Must set correct value to f so the previous tick contains the solution
      //
      f = f;
    });
    return f;
  } else {
    //
    // If f is not a prime factor, send f+1 to the previous tick
    //
    process.prevTick(function(){
      f = f + 1;
    });
  }
}

console.log(primeFactor(25)); // returns 5