Run the tests on GitHub, and publish the browser demo with GitHub Pages once Pages is switched on

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: ReadycodeAI

.github/workflows/demo.yml

@@ -0,0 +1,40 @@
+# Builds the browser demo (web/) and publishes it with GitHub Pages.
+# It only runs once Pages is switched on for this repository
+# (Settings > Pages > Source: GitHub Actions), or when started by hand.
+name: demo
+
+on:
+  push:
+    branches: [main]
+    paths: ["web/**", "src/core.cjs", "package.json", "package-lock.json"]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  deploy:
+    if: github.event_name == 'workflow_dispatch' || github.event.repository.has_pages
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+      - run: npm ci
+      - run: npm run build:web
+      - uses: actions/upload-pages-artifact@v3
+        with:
+          path: web/dist
+      - id: deployment
+        uses: actions/deploy-pages@v4

.github/workflows/test.yml

@@ -0,0 +1,22 @@
+name: test
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node: [20, 22]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node }}
+          cache: npm
+      - run: npm ci
+      - run: npm test
+      - run: npm run build:web

web/README.md

@@ -8,3 +8,5 @@ npm run build:web      # writes web/dist: index.html, reader-web.js, pdf.worker.
 ```
 
 Host the three files in `web/dist` on any static site (they must be served over http(s), not opened as a file). No server code is needed, so it costs nothing however many people use it.
+
+This repository publishes it automatically with GitHub Pages ([`.github/workflows/demo.yml`](../.github/workflows/demo.yml)) once Pages is switched on (Settings > Pages > Source: GitHub Actions). Every change to `web/` or the engine is then rebuilt and republished.