function uniqueWords(text: string): string[] {
  if(text === "") return []
  const textArray = text.toLowerCase().split(' ')
  const obj = {}
  textArray.forEach(v => {
    obj[v] = (obj[v] || 0) + 1
  })
  return Object.keys(obj).filter(v => obj[v] === 1);
}

// Do not modify: needed to evaluate the result.
export { uniqueWords };