Add ifPowerOf2c (trekhleb#155)

Author: tapaswenipathak

src/algorithms/math/bits/README.md

@@ -91,6 +91,23 @@ inverting all of the bits of the number and adding 1 to it.
 
 > See [switchSign.js](switchSign.js) for further details.
 
+#### Power of 2
+
+This method checks if a number provided is power of two. It uses the property that when
+a power of 2 is `&` with power of 2 minus 1, it would return 0 implying that the provided
+number is power of 2.
+
+```
+Number: 4
+Power of 2: True
+
+Number: 1
+Power of 2: False
+```
+
+> See `ifPowerof2` function for further details.
+
+
 #### Multiply Two Numbers
 
 This method multiplies two integer numbers using bitwise operators.
@@ -156,6 +173,7 @@ When we shift 1 four times it will become bigger than 5.
 
 > See [bitLength.js](bitLength.js) for further details.
 
+
 ## References
 
 - [Bit Manipulation on YouTube](https://www.youtube.com/watch?v=NLKQEOgBAnw&t=0s&index=28&list=PLLXdhg_r2hKA7DPDsunoDZ-Z769jWn4R8)

src/algorithms/math/bits/__test__/ifPowerOf2.test.js

@@ -0,0 +1,8 @@
+import ifPowerOf2 from '../ifPowerOf2';
+
+describe('ifPowerOf2', () => {
+  it('Should return if the number is power of 2 or not', () => {
+    expect(ifPowerOf2(5)).toBe(false);
+    expect(ifPowerOf2(4)).toBe(true);
+  });
+});

src/algorithms/math/bits/ifPowerOf2.js

@@ -0,0 +1,7 @@
+/**
+ * @param {number} number
+ * @return bool
+ */
+export default function ifPowerOf2(number) {
+  return number && (!(number & (number - 1)));
+}