index.js
function _stripKeysWithUndefinedValues(dictionary) {
  for (let k in dictionary) {
    if (dictionary[k] === undefined) {
      delete dictionary[k];
    }
  }
  return dictionary;
}
function _stripKeysWithUndefinedValues(dictionary) {
  for (let k in dictionary) {
    if (dictionary[k] === undefined) {
      delete dictionary[k];
    }
  }
  return dictionary;
}
//////////////////////////////////////////////////////////////////////////// 
destructive -- mutates, returns reference only for convenience