Visioner example

class Encrypt {
  alphabet: string;
  links: {};
  table: string[][];
  constructor(_alpthabet: string) {
    this.alphabet = _alpthabet,
      this.links = this.generateLinks(),
      this.table = this.generateTable();
  }

  generateLinks(): Object {
    let tempLinks: Object = {};
    for (let i = 0; i < this.alphabet.length; i++) {
      tempLinks[this.alphabet[i]] = i;
    }
    return tempLinks;
  }

  generateTable(): string[][] {
    let tempTable: string[][] = [];
    for (let i: number = 0; i < this.alphabet.length; i++) {
      tempTable[i] = [];
      for (let j: number = 0; j < this.alphabet.length; j++) {
        let shiftedPos: number = (j + i) % this.alphabet.length;
        tempTable[i][j] = this.alphabet.charAt(shiftedPos);
      }
    }
    return tempTable;
  }

  encrypt(_string: string, _key: string): string {
    if (_string.length != _key.length) return "Lenth not a same";
    let encryptedString: string = "";
    for (let i: number = 0; i < _string.length; i++) {
      let stringIndex: string = this.links[_string[i]];
      let keyIndex: string = this.links[_key[i]];
      encryptedString += this.table[keyIndex][stringIndex];
    }
    return encryptedString;
  }

  decrypt(_string: string, _key: string): string {
    let decryptedString: string = "";
    if (_string.length != _key.length) return "Lenth not a same";
    for (let i: number = 0; i < _string.length; i++) {
      let keyIndex: number = this.links[_key[i]];
      let secondIndex: number = this.table[keyIndex].findIndex(key => _string[i] === key); //indexOf(_string[i]);
      decryptedString += Object.keys(this.links).find(key => this.links[key] === secondIndex);
    }
    return decryptedString;
  }
}
const enAlphabet: string = "BCDEFGHIJKLMNOPQRSTUVWXYZA";
console.log(enAlphabet.length);
const en = new Encrypt(enAlphabet);
const text: string = "HELLOWORLD";
console.log(text.length);
const key: string = "MAXSMOKEMA";
console.log(key.length);
const encString: string = en.encrypt(text, key);
console.log(encString);
const decryptedString: string = en.decrypt(encString, text);
console.log(decryptedString);