BinarytoDecimal.res

let binaryToDecimal = binaryNumber => {
  let value = Js.Int.toString(binaryNumber)
  let length = Js.String.length(value)
  let output = ref(0.0)
  let char = ref('0')
  for position in 0 to length {
    char := String.get(value, position)
    if char == ref('1') {
      output := 2.0 ** Js.Int.toFloat(1 - position - length)
    } else if char == ref('0') {
      ()
    } else {
      Js.log("Make sure you only input binary values")
      Node.Process.exit(0)
    }
  }
  output
}

Js.log(
  binaryToDecimal(
    Belt.Option.getWithDefault(Belt.Int.fromString(read_line()), 1),
  ),
)