Memoization function for ECMAScript

Memoize.js

// Get the nth fibonacci number, starting from fib(0) == 1
var fib = Memoize(function(n) {
    
    if (n == 0) return 1;
    if (n == 1) return 1;
    
    return fib(n - 1) + fib(n - 2);
    
});


// Define the Memoize function
function Memoize(f) {
    
    // Results of previous calls
    var results = {};
    
    // Return the memoized function
    return function() {
        
        // Need to use JSON.stringify because;
        // Symbol.for([1,2]) === Symbol.for('1,2')
        // results[[1,2]] === results['1,2']
        var key = JSON.stringify(arguments);
        
        // Return the result if we have it cached
        return results[key] || (
            // Otherwise calculate it, cache it, then return it
            results[key] = f.apply(null, arguments)
        );
        
    };
    
}