feat(component-meta): extend component meta

[romhml]

Resolves #5168

Introduces a new macro defineComponentMeta to extend component meta with arbitrary values.

<script setup lang="ts">
defineComponentMeta({
  foo: 'bar'
})
</script>

<template>
  <span />
</template>

Results in the following meta:

{
    bar: 'baz',
    props: [ /* ... */ ],
    // ...
}

[romhml]

@KazariEX I'm wondering if it's a good idea to parse nested objects and arrays by traversing the rest of the AST here. I tried to match the parser for prop default values.

On one side it would be nice for end users to receive plain objects / arrays, but might be a bit heavy on performances.

[romhml]

This is a bit aggressive since it'll walk the entire AST. I'll look into restraining it to the top level of <script setup> and defineComponent.

[KazariEX]

I'm not sure if we can parse defineComponentMeta at language-core so that we can read the node directly without repeat traversal, since it's not useful for tsc and IDE.

[romhml]

I'll look into it!

[KazariEX]

See:

language-tools/packages/component-meta/lib/base.ts

Lines 334 to 344 in 317b0cc

	const vueFile = sourceScript.generated?.root;
	const vueDefaults = vueFile && exportName === 'default'
	? (vueFile instanceof vue.VueVirtualCode ? readVueComponentDefaultProps(vueFile, printer, ts) : {})
	: {};
	const tsDefaults = !vueFile ? readTsComponentDefaultProps(
	componentPath.slice(componentPath.lastIndexOf('.') + 1), // ts | js | tsx | jsx
	snapshot.getText(0, snapshot.getLength()),
	exportName,
	printer,
	ts
	) : {};

We can read ast from sourceFile.generated.root._sfc if it's a .vue file, or try sharing parsed ast if it's a .ts file.