Don't mix ESM import with CJS exports

[brandonchinn178]

index.js currently has both import ... from ... statements and module.exports = ... syntaxes, which are two different import systems.

The current problem I'm facing is I'm trying to bundle a script importing @bjorn3/browser_wasi_shim with webpack, and it fails at buildtime when importing with require() (because @bjorn3/browser_wasi_shim's package.json has an exports field that says index.js is only importable via import statements) and fails at runtime when importing with import (because webpack throws an error if an ESM module tries to set module.exports)

https://stackoverflow.com/a/42450109/4966649

Repro:

mkdir src
echo 'import { WASI } from "@bjorn3/browser_wasi_shim"' > src/index.js
npm install webpack webpack-cli @bjorn3/browser_wasi_shim
npx webpack
node dist/main.js

Expected clean exit, got Error: ES Modules may not assign module.exports or exports.*, Use ESM export syntax, instead

---

Less importantly, it would be great if @bjorn3/browser_wasi_shim could provide a UMD build so that it's easy to just do something like

<script src="//unpkg.com/@bjorn/browser_wasi_shim"></script>
<script>
  const { WASI } = window['@bjorn/browser_wasi_shim']
  new WASI(...)
</script>

For now, I can just bundle the package myself with webpack.

[bjorn3]

Thanks for the report! I'm currently rather busy, but I will try to get to this tomorrow or thursday.