heroPet = heroPet => {
  const thangData = extractThangTypeSchemaSlug(heroPet)
  if (!thangData) {
    return
  }
  const { slug, thang } = thangData

  return {
    slug,
    thang: _.merge(DEFAULT_THANGTYPE(), thang)
  }
}
Returns properties required to place a hero pet Lank.
@param {Object} heroPetSchema
@returns {Object|undefined} a pet object with slug and thang