Binary array to corresponding decimal in JavaScript

Problem

We are required to write a JavaScript function that takes in a binary array (consisting of only 0 and 1).

Our function should first join all the bits in the array and then return the decimal number corresponding to that binary.

Example

Following is the code −

const arr = [1, 0, 1, 1];
const binaryArrayToNumber = arr => {
   let num = 0;
   for (let i = 0, exponent = 3; i < arr.length; i++) {
      if (arr[i]) {
         num += Math.pow(2, exponent);
      };
      exponent--;
   };
   return num;
};
console.log(binaryArrayToNumber(arr));

Output

11