Handle a button click.

Handle a button click with a standalone Angular component and explicit browser behavior.

import { Component, signal, output } from '@angular/core';
import { bootstrapApplication } from '@angular/platform-browser';

@Component({
    selector: 'app-root',
    standalone: true,
    template: `
        <main data-ready>
            <button (click)="message.set('Clicked')">Try it</button><output>{{ message() }}</output>
        </main>
    `
})
class App {
    message = signal("Waiting");
}

bootstrapApplication(App).catch(console.error);

Expected output EXAMPLE

Click the button.
The output displays “Clicked”.

Details

Use this main.ts in a modern Angular 22 standalone project with an <app-root></app-root> element in index.html. It includes bootstrapApplication. The test uses Angular ahead-of-time compilation with strict template checks, then checks the rendered behavior in Chromium.

✓ Verified

Tested on Ubuntu 24.04.3 LTS · 2026-11-02 18:47:49 UTC · Node.js v24.15.0; Chromium 141.0.7390.37 · @angular/common 22.2.3; @angular/compiler 22.2.3; @angular/core 22.2.3; @angular/forms 22.2.3; @angular/platform-browser 22.2.3; esbuild 0.28.2; playwright 1.56.0; rxjs 7.8.2; @angular/compiler-cli 22.2.3; typescript 6.0.3

Test inputs, results and environment

The exact published code ran in a dedicated Linux test container with prepared inputs. Dedicated test container, external networking disabled, read-only root, temporary per-example working directory. Browser network requests are blocked. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.

Architecture / host kernel: x86_64 / 6.18.54.1-microsoft-standard-WSL2
Snippet identity / locale: uid=65534, gid=65534 (unprivileged) / C.UTF-8
Interpreter invocation: Compile with Angular ngc (strict TypeScript and strictTemplates); bundle the exact published component with esbuild; mount it in Chromium and execute browser assertions
Container image ID: sha256:c9bce90110f636fe04907469a37e9c8ac888171fd569cbf87101743ec7cdf099
Code SHA-256: a032be6bdf4c546a346123409367e2a658f5c59daff148a99d5567144793533b
Dependencies: @angular/common 22.2.3; @angular/compiler 22.2.3; @angular/core 22.2.3; @angular/forms 22.2.3; @angular/platform-browser 22.2.3; esbuild 0.28.2; playwright 1.56.0; rxjs 7.8.2; @angular/compiler-cli 22.2.3; typescript 6.0.3

Test input setup

These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.

The harness supplies index.html and mounts the published component with locally installed, pinned dependencies.

Observed standard output

Expected output describes the rendered page. The standard-output record below is the browser test harness receipt; the additional assertions check the result and interactions.

Handle a button click: browser checks passed.

Exit code: 0. Standard error: empty. Validation: Shape/content assertions. System-dependent values above are one recorded run.

Additional assertions that passed

Checks recorded by the test harness. Where Python assertions are shown, browser cases use Playwright and simulator cases may inspect pin transitions: result.stdout is captured output, work is the temporary directory, and Path is pathlib.Path. The harness also imports json and csv.

await page.getByRole('button').click(); await text('output','Clicked');