my_fib_solution.js

var yourself = {
    fibonacci_lookup : {0: 0, 1: 1},
    fibonacci : function(n) {
        if (this.fibonacci_lookup[n] !== undefined) {
            return this.fibonacci_lookup[n];
        }
        else {
            var result = this.fibonacci(n - 1) +
                this.fibonacci(n - 2);
                
            this.fibonacci_lookup[n] = result;
            
            return result;
        }
    }
};