Reactive Base 64 Encoder & Decoder

Online base 64 encoder/decoders are a dime a dozen online. Just do a search on Google for them and you'll see thousands of them. So many of them are inadequate. It's the current year, you shouldn't have to press a button to encode your string.

Note: JavaScript's native atob() and btoa() functions use UTF-8 as their encoding. This means this program does too.