breaking: remove legacy package.json files

[benmccann]

Now that we only support newer versions of Node we can simply rely on exports.

This is a breaking change because it requires bundlers to be able to handle the exports field. This is the case for

• Vite 3/4
• Rollup 2/3 (using @rollup/plugin-node-resolve)
• Webpack 5

If you're relying on a bundler that does not know how to deal with export maps, you need to update its version to one that supports it (like webpack 4->5) or switch to another bundler.

[vercel]

@benmccann is attempting to deploy a commit to the Svelte Team on Vercel.

A member of the Team first needs to authorize it.

[dummdidumm]

Is it safe to do this? It's not only about the node version, but also about bundlers. Do all recent versions of Rollup/Webpack/Vite and our REPL auto-detect and use the package exports correctly?

[benmccann]

I think this way is actually more safe. Everything handles exports at this point. The package.json files take precedence over exports and as much as I've tried to fix it, Vite fails to handle it which we're currently working around with certain config.

[benmccann]

Hmm. Actually, webpack 4 may not support it. So I guess there's a question of whether we want to drop support for webpack 4 or not.

It looks to me that about half of webpack users are still on webpack 4. And it looks like about 16% of Svelte users are on webpack: https://npmcharts.com/compare/@sveltejs/vite-plugin-svelte,rollup-plugin-svelte,svelte-loader?log=false&interval=7. So it'd probably be about 8% of users that are on webpack 4 and would need to stay on Svelte 3 until they're able to upgrade to webpack 5.

[benmccann]

@non25 @syvb do you have thoughts on whether we could drop webpack 4 support in Svelte 4?

[non25]

If they are reluctant enough to not upgrade webpack to v5 to this day, then I think they definitely won't be upgrading svelte to v4 anytime soon. 😁

I'm kinda out of the loop on what your plans are regarding svelte 4 and what it will require to refactor in user's 5-40k LoC apps. 🤷‍♂️

[benmccann]

Thanks. There will be a few breaking changes in Svelte 4 like dropping older versions of Node, but hopefully nothing terribly bad. You can see more on https://svelte.dev/roadmap if you're interested

[syvb]

Dropping Webpack 4 support sounds reasonable to me - Webpack 5 has been out for a while now, and people who are still on Webpack 4 probably won't want to update Svelte either. And updating Webpack 4 -> 5 isn't particularly difficult.

[dummdidumm]

We can't get rid of this line because else TypeScript without moduleResolution: bundler won't find the type definitions anymore.

[benmccann]

this PR is trashed. closing in favor of #8515