feat: expose instance property from render

Author: DylanPiercey

package-lock.json

@@ -46,14 +46,14 @@ test("fails when rerendering", async () => {
   await expect(
     rerender({ name: "Dylan" })
   ).rejects.toThrowErrorMatchingInlineSnapshot(
-    `"Components cannot re-render on the server side"`
+    `"Components cannot re-render on the server side."`
   );
 });
 
 test("fails when checking emitted events", async () => {
   const { emitted } = await render(Clickable);
   expect(() => emitted("button-click")).toThrowErrorMatchingInlineSnapshot(
-    `"Components should not emit events on the server side"`
+    `"Components should not emit events on the server side."`
   );
 });
 
@@ -74,3 +74,10 @@ test("fails when emitting events", async () => {
     `"Cannot perform client side interaction tests on the server side. Please use @marko/testing-library in a browser environment."`
   );
 });
+
+test("fails when trying to read instance", async () => {
+  const result = await render(Clickable);
+  expect(() => result.instance).toThrowErrorMatchingInlineSnapshot(
+    `"Cannot access component instance for server side tests."`
+  );
+});

src/__tests__/render.server.ts

@@ -71,6 +71,7 @@ export async function render<T extends Template>(
 
   return {
     container,
+    instance,
     emitted<N extends string = "*">(
       type?: N extends InternalEventNames ? never : N
     ) {

src/index-browser.ts

@@ -31,6 +31,7 @@ export async function render<T extends Template>(
 ): Promise<
   BoundFunctions<typeof Queries> & {
     container: HTMLElement | DocumentFragment;
+    instance: any;
     debug: typeof testingLibraryScreen["debug"];
     emitted<N extends string = "*">(
       type?: N extends InternalEventNames ? never : N
@@ -83,16 +84,21 @@ export async function render<T extends Template>(
 
   return {
     container,
+    get instance(): any {
+      throw new Error(
+        "Cannot access component instance for server side tests."
+      );
+    },
     emitted<N extends string = "*">(
       // eslint-disable-next-line @typescript-eslint/no-unused-vars
       type?: N extends InternalEventNames ? never : N
     ): NonNullable<EventRecord[N]> {
-      throw new Error("Components should not emit events on the server side");
+      throw new Error("Components should not emit events on the server side.");
     },
     // eslint-disable-next-line @typescript-eslint/no-unused-vars
     rerender(newInput?: typeof input): Promise<void> {
       return Promise.reject(
-        new Error("Components cannot re-render on the server side")
+        new Error("Components cannot re-render on the server side.")
       );
     },
     cleanup() {