Add propagation metadata to the TransformResult (#860)

.changeset/clean-sloths-try.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/compiler': minor
+---
+
+Add propagation metadata to the TransformResult

cmd/astro-wasm/astro-wasm.go

@@ -179,6 +179,7 @@ type TransformResult struct {
 	ClientOnlyComponents []HydratedComponent     `js:"clientOnlyComponents"`
 	ContainsHead         bool                    `js:"containsHead"`
 	StyleError           []string                `js:"styleError"`
+	Propagation          bool                    `js:"propagation"`
 }
 
 // This is spawned as a goroutine to preprocess style nodes using an async function passed from JS
@@ -412,6 +413,7 @@ func Transform() any {
 					ClientOnlyComponents: clientOnlyComponents,
 					ContainsHead:         doc.ContainsHead,
 					StyleError:           styleError,
+					Propagation:          doc.HeadPropagation,
 				}
 				switch transformOptions.SourceMap {
 				case "external":

internal/node.go

@@ -96,6 +96,7 @@ type Node struct {
 	ClientOnlyComponents     []*HydratedComponentMetadata
 	HydrationDirectives      map[string]bool
 	ContainsHead             bool
+	HeadPropagation          bool
 
 	Type      NodeType
 	DataAtom  atom.Atom

internal/transform/transform.go

@@ -46,6 +46,7 @@ func Transform(doc *astro.Node, opts TransformOptions, h *handler.Handler) *astr
 		}
 		if HasAttr(n, TRANSITION_ANIMATE) || HasAttr(n, TRANSITION_NAME) || HasAttr(n, TRANSITION_PERSIST) {
 			doc.Transition = true
+			doc.HeadPropagation = true
 			getOrCreateTransitionScope(n, &opts, i)
 		}
 		if len(definedVars) > 0 {

packages/compiler/src/shared/types.ts

@@ -89,6 +89,7 @@ export interface TransformResult {
   hydratedComponents: HydratedComponent[];
   clientOnlyComponents: HydratedComponent[];
   containsHead: boolean;
+  propagation: boolean;
 }
 
 export interface SourceMap {

packages/compiler/test/transition/meta.ts

@@ -0,0 +1,20 @@
+import { test } from 'uvu';
+import * as assert from 'uvu/assert';
+import { transform } from '@astrojs/compiler';
+
+const FIXTURE = `
+<div transition:animate="slide"></div>
+`;
+
+let result;
+test.before(async () => {
+  result = await transform(FIXTURE, {
+    resolvePath: async (s) => s,
+  });
+});
+
+test('tagged with propagation metadata', () => {
+  assert.equal(result.propagation, true);
+});
+
+test.run();