ROT13 decoder

i_love_onsya.ts

function genLookUpTable(k: string, v: string) {
  return k.split('').map((c, i) => { return { [c]: v[i] } }).reduce((a, c) => Object.assign(a, c))
}

function decodeROT13(code: string): string {
  // https://www.wikiwand.com/ja/ROT13#/%E5%AF%BE%E7%85%A7%E8%A1%A8%E3%81%AB%E3%82%88%E3%82%8B%E5%AE%9F%E8%A3%85
  const lookupTable = genLookUpTable(
    'NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm',
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
  );
  return code.split('').map(c => lookupTable[c]).join('')
}

// HATENA
console.log(decodeROT13('UNGRAN'))