Faster Recursions The memoizer function will take an initial 'cache' array and the 'operation' function. It returns a 'self' function that manages the cache store, this 'self' function calls the 'operation' function only when there is a 'cache' miss, ultimately improves performance.

memoizer.js

var memoizer = function (cache, operation) {
    var self = function (n) {
        var result = cache[n];
        if (typeof result !== 'number') {
            result = operation(self, n);
            cache[n] = result;
        }
        return result;
    };
    return self;
};