1. Run npm run build:broken to see the output the breakage
2. Run npm run build:working to see the output of the working version

The two tsconfig*.json files are the exact same, except that 1 uses "module": "node" (the working one) and 1 uses "module": "NodeNext" (broken one)

Add a "types": "{file-name}.mjs.d.ts" for each export

See this link under tools/builder/packages.config.ts.

Check out the branch fix-demo. The readme will change.

NOTE That branch is treated separately from this one. You'll want to have yarn and v16.16.0 of node installed.