@AntaresT_luiz-emidio.js

function convertBinary(value) {
  value = value.toString()
  var decimal = 0
  for (let count = value.length - 1, i = 0; count >= 0; count--, i++){
    decimal += value[count] * Math.pow(2, i);
  }
  console.log(decimal);
}

convertBinary('111101')
convertBinary(111101)