[Markdoc] Support automatic image optimization with `experimental.assets` (#6630)

* wip: scrappy implementation. It works! 🥳

* chore: add code comments on inline utils

* fix: code cleanup, run on experimental.assets

* feat: support ~/assets alias

* fix: spoof `astro:assets` when outside experimental

* test: image paths in dev and prod

* feat: support any vite alias with ctx.resolve

* fix: avoid trying to process absolute paths

* fix: raise helpful error for invalid vite paths

* refactor: revert URL support on emitAsset

* chore: lint

* refactor: expose emitESMImage from assets base

* wip: why doesn't assets exist

* scary chore: make @astrojs/markdoc truly depend on astro

* fix: import emitESMImage straight from dist

* chore: remove type def from assets package

* chore: screw it, just ts ignore

* deps: rollup types

* refactor: optimize images during parse step

* chore: remove unneeded `.flat()`

* fix: use file-based relative paths

* fix: add back helpful error

* chore: changeset

* deps: move astro back to dev dep

* fix: put emit assets behind flag

* chore: change to markdoc patch

1 files changed, 9 insertions, 0 deletions

diff --git a/packages/integrations/markdoc/src/utils.ts b/packages/integrations/markdoc/src/utils.ts
index 275c711f0..9d6e5af26 100644
--- a/packages/integrations/markdoc/src/utils.ts
+++ b/packages/integrations/markdoc/src/utils.ts
@@ -145,3 +145,12 @@ const componentsPropValidator = z.record(
 export function isCapitalized(str: string) {
 	return str.length > 0 && str[0] === str[0].toUpperCase();
 }
+
+export function isValidUrl(str: string): boolean {
+	try {
+		new URL(str);
+		return true;
+	} catch {
+		return false;
+	}
+}