Convert text to number JavaScript

first you need to define each letter to it’s number and each number to it’s letter
then you would grab the letter from the inputted number or the number from the inputted letter

the challange was reversing numbers back to letters in this case because the function will match each number to it’s corresponding letter, so i made each letter have 2 numbers and now when the functions reverse the number it will do that with 2 numbers at the time knowing that each 2 numbers is a letter.

Example here

https://jsfiddle.net/3m2hj1a7/1/

function convertTextAndNumber(input) {
  const alphabetMapping = {
    A: '01', B: '02', C: '03', D: '04', E: '05', F: '06', G: '07', H: '08', I: '09', J: '10',
    K: '11', L: '12', M: '13', N: '14', O: '15', P: '16', Q: '17', R: '18', S: '19',
    T: '20', U: '21', V: '22', W: '23', X: '24', Y: '25', Z: '26'
  };

  const reverseAlphabetMapping = {
    '01': 'A', '02': 'B', '03': 'C', '04': 'D', '05': 'E', '06': 'F', '07': 'G', '08': 'H', '09': 'I', '10': 'J',
    '11': 'K', '12': 'L', '13': 'M', '14': 'N', '15': 'O', '16': 'P', '17': 'Q', '18': 'R', '19': 'S',
    '20': 'T', '21': 'U', '22': 'V', '23': 'W', '24': 'X', '25': 'Y', '26': 'Z'
  };

  function textToNumber(text) {
    const uppercaseText = text.toUpperCase();
    return Array.from(uppercaseText).map(letter => alphabetMapping[letter] || '').join('');
  }

  function numberToText(number) {
    const resultText = [];
    
    for (let i = 0; i < number.length; i += 2) {
      const letterCode = number.substr(i, 2);
      if (reverseAlphabetMapping[letterCode]) {
        resultText.push(reverseAlphabetMapping[letterCode]);
      }
    }

    return resultText.join('');
  }

  // Check if the input contains only numbers to determine the direction of conversion
  const isNumeric = /^d+$/.test(input);

  if (isNumeric) {
    return numberToText(input);
  } else {
    return textToNumber(input);
  }
}

// Example usage
const inputText = 'HelloWorld';
const inputNumber = '08051212152315181204';

console.log(convertTextAndNumber(inputText));  // Output: '08051212152315181204'
console.log(convertTextAndNumber(inputNumber)); // Output: 'HelloWorld'