Added DigitalRoot in Math Module

Maths/DigitalRootAlgorithm.js

@@ -0,0 +1,32 @@
+/**
+ * Digital Root of n by Recursive Approach
+ * Time Complexity : O(1) - Mathematical Formula
+ * Time Complexity : O(log n) - Recursive Approach
+ * For more info: https://en.wikipedia.org/wiki/Digital_root
+ * 
+ * Mathematical Formula: DigitalRoot(n)= 1 + (n - 1) mod 9
+ * Recursive Formula: DigitalRoot(n)= n if n<10 else if digitalRoot(sumOfDigits)
+ * 
+ * @param {number} n 
+ * @returns {number}- digital root of n
+ * @description
+ * The digital root of a non-negative integer is the single digit value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit sum. The process continues until a single-digit number is reached.
+ */
+
+
+const digitalRoot = (n) => {
+  if (n === 0) return 0;
+  return 1 + (n - 1) % 9;
+};
+
+const recursiveDigitalRoot = (n) => {
+  if (n < 10) return n;
+  let sum = 0;
+    while (n > 0) { 
+        sum += n % 10;
+        n = Math.floor(n / 10);
+    }
+  return recursiveDigitalRoot(sum);
+}
+
+export { digitalRoot,recursiveDigitalRoot };