It requires flow analysis, which is really hard to get right. I don't think there's a tree-shaking library that uses the TypeScript compiler API for static analysis purposes. Maybe because it would be slow?
edit: The creator of Terser is working on flow analysis for his new minifier, according to him[1].
edit: The creator of Terser is working on flow analysis for his new minifier, according to him[1].
[1]: https://github.com/terser/terser/issues/1410#issuecomment-17...