Function to sum an object values using recursion

functionalObjSum.js

// This is super slow though: http://jsperf.com/summing-objects/2

var sumObj = function (object) {
  if (Object.keys(object).length) {
    var firstKey = Object.keys(object)[0];
    var clone = Object.assign({}, object);
    delete clone[firstKey];
    return parseInt(object[firstKey]) + sumObj(clone);
  }

  return 0;
};

Looks even neater with ES6:

const sumObj = obj => Object.keys(obj).reduce((sum, next) => sum + object[next], 0)