ESM support

[btakita]

fixes #977

[btakita]

This PR does not work in vite browsers builds. I will look into a solution to support browsers as well.

Uncaught TypeError: import_module.createRequire is not a function
    <anonymous> papaparse.mjs:2

[btakita]

With the latest force push, I added the esm directory, which supports esm + browser & esm + module exports, using esm/package.json. ESM & vite browser builds are now supported.

{
	"main": "./index.mjs",
	"browser": "./index.browser.mjs"
}

"browser" takes precedence over "main" & "module" takes precedence over "browser", which is why I'm using "main" & "browser". I have tested this in my astro.js/vite browser & server side builds.

[btakita]

Here is my astro test page:

---
---
<script>
	import Papa from 'papaparse'
	console.debug('/|debug|1', { Papa, 'globalThis.Papa': globalThis.Papa })
</script>

Which has the console output:

[btakita]

There's a problem with the latest force pushed commit. The vite server side build seems to use the "browser" import, which causes an error:

ReferenceError: require is not defined
    at new DuplexStreamStreamer (/@fs/home/brian/work/portfoliome/censible-core/vendor/PapaParse/papaparse.js:920:16)

Looking into another fix for this...

[btakita]

If vite fixes the issue vitejs/vite#12253, then this PR should work.

In the meantime, I added https://github.com/btakita/PapaParse/tree/vite-plugin-top-level-await, which will work in server side vite builds using the vite-plugin-top-level-await plugin package.

[JonET]

Would this allow us to use esm modules in angular-cli as well? Or would more work need to be done for that? Trying to avoid the "optimization bailouts" warning.

[jschang19]

This modification works for my Nuxt3 project deploying on Cloudflare worker, where I couldn't deploy LLaMAindex since the current version doesn't come with an ESM support. Thx for your contribution!