gistfile1.js

// Recursively sum integer properties of an object
var sumObject = function (source, target) {
  Object.keys(source).forEach(function (key) {
    if (typeof source[key] === "object") {
      if (!target[key]) target[key] = {};
      target[key] = sumObject(source[key], target[key]);
    }
    if (typeof source[key] === "number") {
      if (!target[key]) target[key] = 0;
      target[key] += source[key];
    }
  });
  return target;
};