This repo shows the effects of a tree-shakeable version of preact/compat. webpack.config.js has comments showing the relevant configuration/ possible deoptimizations. Install dependencies and run yarn/npm run build to see the bundle analysis.
Running this on my machine, I got the following results for the built bundle:
- 5.69kb gzipped when using the tree-shakeable compat
- 6.89kb gzipped when using the existing
preact/compat