Kaprekar constant method

kaprekar.ts

function kaprekar(value: string, steps: number = 0) {
  if (steps > 100) {
    console.error('Too many steps');
    return;
  }
  const kaprekarConstant = '6174';
  if (value.length !== 4) {
    console.error('Invalid value');
    return;
  }
  const individuals = value.split('');

  if (areAllElementsSame(individuals)) {
    console.error('At least two digits must be different');
    return;
  }
  const largest = individuals.sort((a, b) => parseInt(b) - parseInt(a)).map(Number).join('');

  const lowest = individuals.sort((a, b) => parseInt(a) - parseInt(b)).map(Number).join('');
  const newValue = parseInt(largest) - parseInt(lowest);
  console.debug(`Value recieved: ${value} and New value: ${newValue}`);
  if (newValue.toString() === kaprekarConstant) {
    console.info(`Found constant in ${steps} steps:`);
    return;
  }

  kaprekar(newValue.toString(), steps + 1);
}


function areAllElementsSame(arr: string[]): boolean {
  return arr.every(element => element === arr[0]);
}

kaprekar('9912');