# JavaScript - Next power of two of a given number

## JavaScript Bit Manipulation: Exercise-4 with Solution

Write a JavaScript program to find next power of two of a given number.

A power of two is a number of the form 2n where n is an integer, that is, the result of exponentiation with number two as the base and integer n as the exponent.

The first ten powers of 2 for non-negative values of n are: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, ...

**Test Data:**

(1) -> 1

(4) -> 4

(9) -> 16

("15") -> "It must be number!"

**Sample Solution: **

**JavaScript Code:**

```
const next_Power_Of_Two = (num) => {
if (typeof num != "number") {
return 'It must be number!'
}
if (num > 0 && (num & (num - 1)) === 0)
return num
let result = 1
while (num > 0)
{
result = result << 1
num = num >> 1
}
return result
}
console.log(next_Power_Of_Two(1))
console.log(next_Power_Of_Two(4))
console.log(next_Power_Of_Two(9))
console.log(next_Power_Of_Two("15"))
```

Sample Output:

1 4 16 It must be number!

**Flowchart: **

**Live Demo: **

See the Pen javascript-bit-manipulation-exercise-4 by w3resource (@w3resource) on CodePen.

* To run the code mouse over on Result panel and click on 'RERUN' button.*

**Improve this sample solution and post your code through Disqus**

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## JavaScript: Tips of the Day

**function and arguments**

const person = { name: 'Lydia Hallie', hobbies: ['coding'], }; function addHobby(hobby, hobbies = person.hobbies) { hobbies.push(hobby); return hobbies; } addHobby('running', []); addHobby('dancing'); addHobby('baking', person.hobbies); console.log(person.hobbies);

The addHobby function receives two arguments, hobby and hobbies with the default value of the hobbies array on the person object.

First, we invoke the addHobby function, and pass "running" as the value for hobby and an empty array as the value for hobbies. Since we pass an empty array as the value for y, "running" gets added to this empty array.

Then, we invoke the addHobby function, and pass "dancing" as the value for hobby. We didn't pass a value for hobbies, so it gets the default value, the hobbies property on the person object. We push the hobby dancing to the person.hobbies array.

Last, we invoke the addHobby function, and pass "bdaking" as the value for hobby, and the person.hobbies array as the value for hobbies. We push the hobby baking to the person.hobbies array.

After pushing dancing and baking, the value of person.hobbies is ["coding", "dancing", "baking"]

Ref: https://bit.ly/2Hcpkm6

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