function combineClassObjects (...collections) {
  const finalSet = new Set([])

  collections.forEach(set => {
    if (Array.isArray(set)) {
      finalSet.forEach(className => finalSet.add(className))
    } else {
      finalSet.add(set)
    }
  })

  return Array.from(finalSet)
}
Combines collections of style classes into one collection
@param  {Array<String | String[]>} collections The collections to combine.
@returns {Array<String>}