How to conditionally build an object in ES6 – 1

conditional-object-snippet1.js

function episodeParser(data) {
  const { id, 
   title,
   description,
   optionalField,
   anotherOptionalField
  } = data
  const parsedEpisode = { guid: id, title, summary: description }
  if (optionalField) {
    parsedEpisode.optionalField = optionalField
  } else if (anotherOptionalField) {
    parsedEpisode.anotherOptionalField = anotherOptionalField
  }
  // and so on
  return parsedEpisode
}