euclideanAlgorithm.js

/**
 * Recursive version of Euclidean Algorithm of finding greatest common divisor (GCD).
 * @param {number} originalA
 * @param {number} originalB
 * @return {number}
 */
export default function euclideanAlgorithm(originalA, originalB) {
  // Make input numbers positive.
  const a = Math.abs(originalA);
  const b = Math.abs(originalB);

  // To make algorithm work faster instead of subtracting one number from the other
  // we may use modulo operation.
  return (b === 0) ? a : euclideanAlgorithm(b, a % b);
}