A memozation of Fibonacci, implemented for a CodeEval challenge but preserved here for reference.

memoize Fibonacci

function Fibonacci(n) {
  // finds the fibonacci number
  // base case: 0, 1 for F(0) and F(1)

  if (n === 0) {
    return 0;
  } else if (n === 1) {
    return 1;
  } else {
    return Fibonacci(n-1) + Fibonacci(n-2);
  }

}

Function.prototype.memoize = Function.prototype.memoize || function() {
  var self = this, cache = {};
  return function(arg) {
    if (cache[arg]) {
      return cache[arg];
    } else {
      return cache[arg] = self(arg);
    }
  }
}

var memoedFib = Fibonacci.memoize();

console.log('memoed!', memoedFib(12)); // will print 144