function mergeObjects(var_args) {
  var merged = {};
  var objects = Array.prototype.slice.call(arguments);
  objects.forEach(function(obj) {
    Object.keys(obj).forEach(function(key) {
      merged[key] = obj[key];
    });
  });
  return merged;
}
Merges objects into a single object.
TODO(dpapad): Replace this with Object.assign once it becomes available in
node.
@param {...!Object} var_args The objects to be merged.
@return {!Object} The merged object.