1 files changed, 18 insertions, 12 deletions
diff --git a/packages/integrations/markdoc/src/runtime.ts b/packages/integrations/markdoc/src/runtime.ts
index 5a59d5fef..939e6d602 100644
--- a/packages/integrations/markdoc/src/runtime.ts
+++ b/packages/integrations/markdoc/src/runtime.ts
@@ -13,26 +13,19 @@ export { default as Markdoc } from '@markdoc/markdoc';
  * Called on each file's individual transform.
  * TODO: virtual module to merge configs per-build instead of per-file?
  */
-export function setupConfig(
+export async function setupConfig(
 	userConfig: AstroMarkdocConfig,
-	entry: ContentEntryModule,
-	markdocConfigPath?: string
-): Omit<AstroMarkdocConfig, 'extends'> {
+	entry: ContentEntryModule
+): Promise<Omit<AstroMarkdocConfig, 'extends'>> {
 	let defaultConfig: AstroMarkdocConfig = {
 		...setupHeadingConfig(),
 		variables: { entry },
 	};
 
 	if (userConfig.extends) {
-		for (const extension of userConfig.extends) {
+		for (let extension of userConfig.extends) {
 			if (extension instanceof Promise) {
-				throw new MarkdocError({
-					message: 'An extension passed to `extends` in your markdoc config returns a Promise.',
-					hint: 'Call `await` for async extensions. Example: `extends: [await myExtension()]`',
-					location: {
-						file: markdocConfigPath,
-					},
-				});
+				extension = await extension;
 			}
 
 			defaultConfig = mergeConfig(defaultConfig, extension);
@@ -42,6 +35,19 @@ export function setupConfig(
 	return mergeConfig(defaultConfig, userConfig);
 }
 
+/** Used for synchronous `getHeadings()` function */
+export function setupConfigSync(
+	userConfig: AstroMarkdocConfig,
+	entry: ContentEntryModule
+): Omit<AstroMarkdocConfig, 'extends'> {
+	let defaultConfig: AstroMarkdocConfig = {
+		...setupHeadingConfig(),
+		variables: { entry },
+	};
+
+	return mergeConfig(defaultConfig, userConfig);
+}
+
 /** Merge function from `@markdoc/markdoc` internals */
 function mergeConfig(configA: AstroMarkdocConfig, configB: AstroMarkdocConfig): AstroMarkdocConfig {
 	return {