[LiveComponent] Adding rollup to make an esm build

[weaverryan]

Q	A
Bug fix?	yes
New feature?	no
Tickets	Addresses Bug A from #102
License	MIT

Hi!

This changes how LiveComponent is bundle. There are a few important pieces:

1. I decided to continue support IE 11. The difference in the unminified file size (including polyfills) is about 5kg (56kb vs 61kb).

2. I'm building ESM only right now. I have considered a UMD build... but I don't know if there is a real use-case. In practice, this library will always be used in a build system... but I cannot find any other libraries that only output ESM.

3. This sets babelHelpers to runtime, which means that instead of embedding the babel helpers (like _typeof

   ux/src/LiveComponent/assets/dist/live_controller.js

   Line 3 in e239983

   function _typeof(obj) { "@babel/helpers - typeof"; if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }; } return _typeof(obj); }

   ) in every file, they all import from @babel/runtime.

4. We're testing the src/ files, not the dist/ files.

I don't have a lot of experience with compiling files for the frontend - and there seems to be a lot of variability on how to do it. If you see anything weird, let me know :).

Cheers!

[Kocal]

In the Rollup world we usually automate external by using the following code:

import pkg from './package.json';

export default [
  {
    // ...
    external: Object.keys(pkg.dependencies)
  }
]

WDYT?

[weaverryan]

I want to do whatever is standard :). But, the @babel/runtime needed to be a regex so that it matches all the individual, nested paths that are actually imported - like @babel/runtime/.... I got that from the note in this section - https://github.com/rollup/plugins/tree/master/packages/babel#babelhelpers

[Kocal]

Oh alright, I wasn't aware of that

[Kocal]

Do you think it would be interesting to also configure module field?

[weaverryan]

Even though they're identical, yea, I think that's a good idea.