feat: add 'after' request context method (#677)

docs/api-reference/components/request-context.md

@@ -37,6 +37,9 @@ export default function ServerComponent(props, requestContext: RequestContext) {
 
     // Add styles
     css,
+
+    // Run tasks after the response is sent
+    after,
   } = requestContext;
   // ... Server component implementation ...
 }
@@ -320,3 +323,29 @@ css`
 > We recommend using the `css` template literal for specific cases such as generating CSS animations based on dynamic JavaScript variables.
 
 For more details, refer to the [Template literal `css`](/building-your-application/components-details/web-components#template-literal-css) documentation.
+
+## `after`
+
+`after(cb: () => void): void`
+
+The `after` method allows you to schedule work to be executed after a response (or prerender) is finished. This is useful for tasks and other side effects that should not block the response, such as logging and analytics.
+
+It can be used everywhere when you have access to the `RequestContext` (Middleware, API routes, Server components, etc).
+
+Example:
+
+```tsx
+import { type RequestContext } from "brisa";
+
+export default function SomeComponent({}, { after }: RequestContext) {
+  after(() => {
+    console.log("The response is sent");
+  });
+
+  return <div>Some content</div>;
+}
+```
+
+> [!NOTE]
+>
+> **Good to know**:  `after` is not a Dynamic API and calling it does not cause a route to become dynamic. If it's used within a static page, the callback will execute at build time.

packages/brisa/src/types/index.d.ts

@@ -353,6 +353,26 @@ export interface RequestContext extends Request {
    * - [How to use `css`](https://brisa.build/api-reference/components/request-context#css)
    */
   css(strings: TemplateStringsArray, ...values: string[]): void;
+
+  /**
+   * Description:
+   *
+   * The `after` method is used to execute a function after the response has been sent.
+   *
+   * Example:
+   *
+   * ```ts
+   * after(() => console.log('Hello World'));
+   * ```
+   *
+   * This log will be executed after the response has been sent.
+   *
+   * Docs:
+   *
+   * - [How to use `after`](https://brisa.build/api-reference/components/request-context#after)
+   *
+   */
+  after(fn: Effect): void | Promise<void>;
 }
 
 type Effect = () => void | Promise<void>;

packages/brisa/src/utils/extend-request-context/index.test.ts

@@ -374,5 +374,32 @@ describe('brisa core', () => {
       });
       expect(requestContext.initiator).toBe(Initiator.SERVER_ACTION);
     });
+
+    it('should add tasks to the request with "after"', () => {
+      const requestContext = extendRequestContext({
+        originalRequest: new Request('https://example.com'),
+      });
+
+      const mockAfter = mock(() => {});
+      requestContext.after(() => mockAfter());
+
+      expect((requestContext as any)._tasks).toHaveLength(1);
+      expect(mockAfter).not.toHaveBeenCalled();
+    });
+
+    it('should keep tasks from one req to another one', () => {
+      const requestContext = extendRequestContext({
+        originalRequest: new Request('https://example.com'),
+      });
+
+      requestContext.after(() => {});
+      expect((requestContext as any)._tasks).toHaveLength(1);
+
+      const requestContext2 = extendRequestContext({
+        originalRequest: requestContext,
+      });
+
+      expect((requestContext as any)._tasks).toHaveLength(1);
+    });
   });
 });

packages/brisa/src/utils/extend-request-context/index.ts

@@ -29,6 +29,12 @@ export default function extendRequestContext({
   finalURL,
   id,
 }: ExtendRequestContext): RequestContext {
+  // After tasks
+  originalRequest._tasks ??= [];
+  originalRequest.after = (task) => {
+    originalRequest._tasks.push(task);
+  };
+
   // finalURL
   originalRequest.finalURL =
     finalURL ?? originalRequest.finalURL ?? originalRequest.url;

packages/brisa/src/utils/render-to-readable-stream/index.test.tsx

@@ -3796,6 +3796,35 @@ describe('utils', () => {
       );
     });
 
+    it('should resolve request._tasks after the response stream', async () => {
+      const request = extendRequestContext({
+        originalRequest: extendRequestContext({
+          originalRequest: new Request('http://test.com/en'),
+        }),
+      });
+
+      const mockAfter = mock(() => {});
+      request.after(() => mockAfter());
+
+      const stream = renderToReadableStream(
+        <html>
+          <head></head>
+          <body></body>
+        </html>,
+        { request },
+      );
+
+      const reader = stream.getReader();
+
+      while (true) {
+        const result = await reader.read();
+        if (result.done) break;
+        expect(mockAfter).not.toHaveBeenCalled();
+      }
+
+      expect(mockAfter).toHaveBeenCalled();
+    });
+
     it('should include window.r with the route without i18n', () => {
       const request = extendRequestContext({
         originalRequest: extendRequestContext({

packages/brisa/src/utils/render-to-readable-stream/index.ts

@@ -110,6 +110,9 @@ export default function renderToReadableStream(
 
       controller.close();
 
+      // Resolve tasks from "after" request method
+      await Promise.all((req as any)._tasks.map((task: () => void) => task()));
+
       if (
         isPage &&
         !IS_PRODUCTION &&