Delay emptying of dist folder in package

[kwangure]

Describe the problem

svelte-package currently works as follows 1) Empty dist/ 2) generate Svelte types 3) Emit ts-types. Step 2) and 3) take LOOONG. So if a site-1 depends on package-1, While step 2 and 3 are happening Vite HMR in site-1 sees that there are no files and crashes unrecoverably.

Describe the proposed solution

Change the algorithm to the following:

1. Empty ./svelte-kit/__package__:
2. generate Svelte & TS types into ./.svelte-kit folder
3. Copy output from into ./svelte-kit/__package__ to dist/

https://github.com/sveltejs/kit/blob/master/packages/package/src/index.js#L31

-	rimraf(output);
-	mkdirp(output);
+   rimraf(temp);
+	mkdirp(temp);

	const files = scan(input, extensions);

	if (options.types) {
-		await emit_dts(input, output, options.cwd, alias, files);
+		await emit_dts(input, temp, options.cwd, alias, files);
	}

	for (const file of files) {
-		await process_file(input, output, file, options.config.preprocess, alias, analyse_code);
+		await process_file(input, temp, file, options.config.preprocess, alias, analyse_code);
	}

+	rimraf(output);
+	mkdirp(output);
+	copy(temp, output);

It takes slightly longer because of the copying but it doesn't break apps that are depending dist/.

Alternatives considered

The more nuclear option is to avoid svelte-package altogether and generate types using svelte2tsx using a build script. In a monorepo setup you can get away with not pre-processing etc. and do it in the consuming application.

Importance

would make my life easier

Additional Information

No response

[ghostdevv]

Hey can you provide a minimal reproduction?

[kwangure]

Hey.

https://github.com/kwangure/svelte-package-refresh-repro