関数を変換に組み込む

refactorgram

function base(aReading) {...}
function taxableCharge(aReading) {...}

function enrichReading(argReading) {
  const aReading = _.cloneDeep(argReading);
  aReading.baseCharge = base(aReading);
  aReading.taxableCharge = taxableCharge(aReading);
  return aReading;
}