transliterateHiraganaToKatakana.js

const HIRAGANA = "ぁあぃいぅうぇえぉおかがきぎくぐけげこごさざしじすずせぜそぞただちぢっつづてでとどなにぬねのはばぱひびぴふぶぷへべぺほぼぽまみむめもゃやゅゆょよらりるれろゎわゐゑをんゔゕゖ";
const KATAKANA = "ァアィイゥウェエォオカガキギクグケゲコゴサザシジスズセゼソゾタダチヂッツヅテデトドナニヌネノハバパヒビピフブプヘベペホボポマミムメモャヤュユョヨラリルレロヮワヰヱヲンヴヵヶ";

function transliterateHiraganaToKatakana(text) {
  var newText = "";
  
  for(let character of text) {
    const codepoint = character.codePointAt(0);
    
    if(codepoint >= 12353 && codepoint <= 12438) {
      newText = newText + String.fromCodePoint(codepoint + 96);
    }
    else {
      newText = newText + character;
    }
  }
  
  return newText;
}

if(transliterateHiraganaToKatakana(HIRAGANA) === KATAKANA) {
  console.log("Conversion successful");
}

if(transliterateHiraganaToKatakana("Latin text") === "Latin text") {
  console.log("Conversion successful");
}

if(transliterateHiraganaToKatakana("Mixedあア") === "Mixedアア") {
  console.log("Conversion successful");
}