An ad hoc, informally-specified, bug-ridden, slow implementation of half of a text adventure game -- or as I like to call it, a compiler.
"an ad-hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp"
Sounds like every metacircular interpreter I've written!
We pack 5 introduces a slew of new static analysis features, including /*#__pure__*/
https://webpack.js.org/blog/2020-10-10-webpack-5-release/
(Every sufficiently advanced dev tool contains an ad-hoc, informally specified compiler?)