Or just stable JS APIs that you can specify on your scripts.

<script vers="3.1"> </script>

<script vers="4.2"> </script>

Yeah. It's a real shame that the language we need batteries-included in the most (because of code size limitations) is one of the most deficient.

I feel like the mess helps discourage it's use. I shouldn't need a Turing machine in order to read a text document.

Sounds a little bit like making https://cdn.polyfill.io/v2/docs/features/ persistent between websites ;-)