Rounding off numbers to some nearest power in JavaScript

We are required to write a JavaScript function that takes in a number and returns a number that can be represented as a power of 2 which is nearest to the input number.

For example: If the input number if 145.

Then the output should be 128 because 145 is the nearest such number to 128 which can be represented as 2^n for some whole number value of n.

Example

The code for this will be −

const num = 145;
const nearestPowerOfTwo = num => {
   // dealing only with non negative numbers
   if(num < 0){
      num *= -1;
   }
   let base = 1;
   while(base < num){
      if(num - base < Math.floor(base / 2)){
         return base;
      };
      base *= 2;
   };
   return base;
};
console.log(nearestPowerOfTwo(num));

Output

The output in the console −

128