var memoizer = function (memo, func) {    var recur = function (n) {        var result = memo[n];        if (typeof result !== ‘number‘) {            result = func (recur, n);        }        return result;    };    return recur;};

var fibonacci = memoizer([0, 1], function (recur, n) {    return recur (n - 1) + recur(n - 2);});