diff --git a/packages/ngtools/webpack/src/resource_loader.ts b/packages/ngtools/webpack/src/resource_loader.ts
index 54873f7b3e1b..cb3cbc234cdb 100644
--- a/packages/ngtools/webpack/src/resource_loader.ts
+++ b/packages/ngtools/webpack/src/resource_loader.ts
@@ -56,7 +56,7 @@ export class WebpackResourceLoader {
     // Simple sanity check.
     if (filePath.match(/\.[jt]s$/)) {
       return Promise.reject(
-        'Cannot use a JavaScript or TypeScript file for styleUrl or templateUrl.',
+        `Cannot use a JavaScript or TypeScript file (${filePath}) in a component's styleUrls or templateUrl.`,
       );
     }