invertPhrase.js

invertPhrase = (phrase) => {
  const characters = [...`abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789?!,.()"`];
  const invertedCharacters = [...`ɐqɔpǝⅎƃɥᴉɾʞʅɯuodbɹsʇnʌʍxʎz∀ꓭϽᗡƎᖵ⅁HIᒋꓘ⅂ꟽNOԀꝹꓤSꓕՈɅϺX⅄Z0⇂↊↋ߤ59𝘓86¿¡ʻ.)(﮼`];
  
  const phraseArray = [...phrase];

  const invertedPhrase = phraseArray.reduce((acc, cur) => {
    const index = characters.indexOf(cur);
  
    if(index < 0) return cur + acc;
    
    return invertedCharacters[index] + acc;
  }, "");

  return invertedPhrase;
}