Fibonacci in Javascript with recursion and cache.

fibonacci.js

#!/usr/bin/env node
"use strict";

var fibonacci = function fib(n) {
  if (typeof fib._cache === 'undefined') {
    fib._cache = {};
  }
  if (fib._cache[n]) {
    return fib._cache[n];
  }

  return fib._cache[n] = (n > 1) ? fib(n -1) + fib(n - 2) : n;
};

var args = global.process.argv.slice(2);

try {
  console.log(fibonacci(args[0]));
} catch (e) {
  console.log(e.toString());
}