feature: preprocessor can change tag attributes like <script lang="ts">

[milahu]

How important is this feature to you?
zero to low priority, mostly cosmetic. browsers ignore extra attributes like <script lang="ts">

Is your feature request related to a problem? Please describe.
currently, preprocessors can not change tag attributes

for example

<script lang="ts">export let name: string</script>

can only be transformed to

<script lang="ts">export let name</script>

but not to

<script>export let name</script>

because preprocessors can only read attributes, but not change them

Describe the solution you'd like
allow preprocessors to to modify attributes
by returning the new attributes in result.attributes

for example, the typescript preprocessor could do

if (attributes.lang != 'ts') return;
delete attributes.lang;
code = compile(code);
return { code, map, attributes };

Describe alternatives you've considered
do nothing, and let browsers ignore extra attributes

related code

svelte/src/compiler/preprocess/index.ts

Lines 274 to 285 in 32775a6

	const processed = await preprocessor({
	content,
	attributes: parse_attributes(attributes),
	filename
	});
	if (processed && processed.dependencies) {
	dependencies.push(...processed.dependencies);
	}
	if (!processed || !processed.map && processed.code === content) {
	return no_change();
	}
	return get_replacement(file_basename, offset, get_location, content, processed, `<${tag_name}${attributes}>`, `</${tag_name}>`);

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.