JSFiddle - React, Tailwind, and code Playground

by Shashank Shekhar

JavaScript

const alphabets = [
  "A",
  "B",
  "C",
  "D",
  "E",
  "F",
  "G",
  "H",
  "I",
  "J",
  "K",
  "L",
  "M",
  "N",
  "O",
  "P",
  "Q",
  "R",
  "S",
  "T",
  "U",
  "V",
  "W",
  "X",
  "Y",
  "Z",
  "a",
  "b",
  "c",
  "d",
  "e",
  "f",
  "g",
  "h",
  "i",
  "j",
  "k",
  "l",
  "m",
  "n",
  "o",
  "p",
  "q",
  "r",
  "s",
  "t",
  "u",
  "v",
  "w",
  "x",
  "y",
  "z"
];

const cryptedAlphabets = [
  "D",
  "E",
  "F",
  "G",
  "H",
  "I",
  "J",
  "K",
  "L",
  "M",
  "N",
  "O",
  "P",
  "Q",
  "R",
  "S",
  "T",
  "U",
  "V",
  "W",
  "X",
  "Y",
  "Z",
  "A",
  "B",
  "C",
  "d",
  "e",
  "f",
  "g",
  "h",
  "i",
  "j",
  "k",
  "l",
  "m",
  "n",
  "o",
  "p",
  "q",
  "r",
  "s",
  "t",
  "u",
  "v",
  "w",
  "x",
  "y",
  "z",
  "a",
  "b",
  "c"
];

const str = `
Ghdu Gldub,

Rxu Mrxuqhb ehjdq lq wkh Dosdfd
Prxqwdlqv. Wklv lv d vwudqjh sodfh
ixoo ri lfh dqg urfnb shdnv. Rqh ri
pb wuxvwhg Exwohuv kdv douhdgb
jrqh plvvlqj. Exulhg pdbeh, xqghu
wkh Eolcdug wkdw hqjxoihg rxu
fdps odvw qljkw.

Vr idu wkh rqob ohdg zh kdyh lv d
qrwh lqvfulehg rq d sodtxh wkdw
vdbv “Wzr urdgv glyhujhg lq d zrrg,
dqg
L wrrn wkh rqh ohvv wudyhohg eb,
Dqg wkdw kdv pdgh doo wkh 
gliihuhqfh”

`;

const stringArr = str.split('')
const decryptedStrArr = [];

stringArr.forEach((word) => {
  if(cryptedAlphabets.includes(word)) {
    const cryptedIndex = cryptedAlphabets.findIndex((item) => item === word);
    const decrypAlpha = alphabets[cryptedIndex];
    decryptedStrArr.push(decrypAlpha);
  } else {
  	decryptedStrArr.push(word);
  }
});

const decryptedString = decryptedStrArr.join('');
console.log(decryptedString);