Convert Binary to decimal with javascript

binarytodecimal.js

// METHOD 1 (IN-BUILT FUNCTION)

function convertBaseToBinary(bin) {
  return parseInt(bin, 2).toString(10); // Convert arguments from one radix/base to radix in toString()/
}

// USING FOR LOOP & parseInt FUNCTION
function bin2dec(bin) {
  var decimal = 0;
  for (var index = bin.length - 1; index >= 0; index--) {
    decimal += parseInt(bin[index]) * Math.pow(2, bin.length - 1 - index);
    return decimal;
  }
}
console.log(bin2dec('101'));
console.log(convertBaseToBinary('101'));