Allow projects to use an extension other than .ts or .js for the entrypoint module.

[shirakaba]

NativeScript currently looks for an {entry}.ts or {entry}.js file as its entrypoint and automatically loads it when the app starts, where entry is defined by the main field in package.json.

Proposal: Allow any source file extensions supported by the Webpack configuration to be resolved; not just strictly ts and js.

Prior work: I once opened a PR towards this (NativeScript/nativescript-dev-webpack#875), but the codebase has been refactored since then. It's still largely the same setup, though: https://github.com/NativeScript/nativescript-dev-webpack/blob/5e4936fc6ba9d6503c8fff3e4dd59e541f49d941/index.js#L76-L96

Benefit: This would allow React apps to use app.tsx or Svelte Native apps to use app.svelte as an entrypoint, allowing them to write TSX or Svelte syntax, etc. It's the only reason that React NativeScript has to use this bewildering React.createElement() call instead of TSX syntax in the entrypoint:

https://github.com/shirakaba/react-nativescript/blob/8327e29f3b6cd62446ba3ea9b84b3293983b07a0/sample/app/app.ts#L33

[rigor789]

I completely agree on this one - in the new webpack implementation (from RFC #2) the main field will be used as-is, allowing you to specify any file as the entry point. Another change from the RFC is that the path is now relative to the package.json and not the app folder.

I added a note in the rfc:

BREAKING CHANGES:

• package.json main should now use a relative path to the package.json instead of the app directory

  For example (given we have a src directory where our app is):

  "main": "app.js" becomes "main": "src/app.js"

  This simplifies things, and will allow ctrl/cmd + clicking on the filename in some editors.

[shirakaba]

Another change from the RFC is that the path is now relative to the package.json and not the app folder.

Ah yes, I support changing "main": "app.js" to "main": "src/app.js", as it reduces the magic. I brought it up as bewildering in a TSC or community call once. Is there a standard procedure for indicating support for an RFC?

[rigor789]

Issues are prior-discussions, but for rfc's you can leave a 👍 on the PR #2 or comment etc.

I feel like generally unless there is major opposition to an RFC - and the TSC also approves it (by leaving an approval on the PR), it can proceed to the "active" stage:
https://github.com/NativeScript/rfcs#reviewing-rfcs

[rigor789]

I'm closing this - as this is already working/included in the webpack RFC/changes.