HomeWork 2

gistfile1.txt

Function.prototype.cached = function(){
  var that = this;
  var cache = {};
  return function(arg){
    if(arg in cache){
      return cache[arg];
    }else{
      cache[arg] = that(arg);
      return cache[arg];
    }
  };
};


function isPrime(num){
  console.log('not in cache');
  var prime = num != 1;
  for ( var i = 2; i < num; i++ ) {
    if ( num % i == 0 ) {
      prime = false;
      break;
    }
  }
  return prime;
}

cachedIsPrime = isPrime.cached();
console.log(cachedIsPrime(11));
console.log(cachedIsPrime(11));
console.log(cachedIsPrime(11));