Check if number is already power of two

Author: indremak

Bit-Manipulation/NextPowerOfTwo.js

@@ -2,10 +2,13 @@
  *
  *  This script will find next power of two
  *    of given number.
+ *  More about it:
+ *   https://www.techiedelight.com/round-next-highest-power-2/
  *
  */
 
 export const nextPowerOfTwo = (n) => {
+  if (n > 0 && (n & (n - 1)) === 0) return n
   let result = 1
   while (n > 0) {
     result = result << 1

Bit-Manipulation/test/NextPowerOfTwo.test.js

@@ -4,12 +4,12 @@ describe('NextPowerOfTwo', () => {
   it.each`
     input    | result
     ${0}     | ${1}
-    ${1}     | ${2}
-    ${2}     | ${4}
+    ${1}     | ${1}
+    ${2}     | ${2}
     ${3}     | ${4}
     ${5}     | ${8}
     ${125}   | ${128}
-    ${1024}  | ${2048}
+    ${1024}  | ${1024}
     ${10000} | ${16384}
   `('returns $result when is given $input', ({ input, result }) => {
     const res = nextPowerOfTwo(input)