Wrap recursion

gistfile1.js

function sum(value) {
    function line(fx) {
        while (fx instanceof Function) {
            fx = fx.call(null);
        }
        return fx;
    }

    function recursion(current, result) {
        return function() {
            if (current === 1) return result;
            return recursion(current - 1, result + current);
        };
    }

    return line(recursion(value, 1)());
}

console.log(sum(50000));