ci: add lighthouse CI

.github/workflows/lighthouse.yml

@@ -0,0 +1,119 @@
+name: Lighthouse Audit
+
+on:
+  pull_request_target:
+    types: [opened, synchronize]
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  lighthouse:
+    if: github.actor != 'dependabot[bot]'
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: ⬇️ Checkout PR code
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+
+      - name: ⏳ Wait for Netlify preview to be live
+        run: |
+          PREVIEW_URL="https://deploy-preview-${{ github.event.pull_request.number }}--expressjscom-preview.netlify.app"
+          echo "PREVIEW_URL=$PREVIEW_URL" >> "$GITHUB_ENV"
+          for i in {1..3}; do
+            if curl -s --head "$PREVIEW_URL" | grep "200 OK" > /dev/null; then
+              echo "Preview is live!"
+              break
+            fi
+            echo "Waiting for Netlify to deploy... ($i/3)"
+            sleep 10
+          done
+
+      - name: ⚙️ Install Lighthouse
+        run: npm install -g lighthouse
+
+      - name: 📊 Run Lighthouse audits
+        run: |
+          mkdir -p lighthouse-report
+          URLS=(
+            "$PREVIEW_URL"
+            "$PREVIEW_URL/en/blog/posts.html"
+            "$PREVIEW_URL/en/support/"
+            "$PREVIEW_URL/en/resources/glossary.html"
+            "$PREVIEW_URL/en/5x/api.html"
+          )
+          echo "[" > lighthouse-report/manifest.json
+          for url in "${URLS[@]}"; do
+            name=$(echo "$url" | sed 's|https://||;s|[/.]|_|g')
+            path="./lighthouse-report/$name.report.json"
+            lighthouse "$url" \
+              --output json \
+              --output-path="$path" \
+              --chrome-flags="--headless"
+            jq -n --arg url "$url" \
+              --argjson summary "$(jq '.categories | {
+                performance: .performance.score,
+                accessibility: .accessibility.score,
+                "best-practices": .["best-practices"].score,
+                seo: .seo.score
+              }' "$path")" \
+              '{url: $url, summary: $summary}' >> lighthouse-report/manifest.json
+            echo "," >> lighthouse-report/manifest.json
+          done
+          sed -i '$ s/,$//' lighthouse-report/manifest.json
+          echo "]" >> lighthouse-report/manifest.json
+
+          # create dummy links file
+          jq -n '{ 
+            '"$(for url in "${URLS[@]}"; do echo "\"$url\": \"$url\","; done | sed '$ s/,$//')"'
+          }' > lighthouse-report/links.json
+
+      - name: 📝 Format comment
+        id: format
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const fs = require('fs');
+
+            const stoplight = res => (res >= 90 ? '🟢' : res >= 75 ? '🟠' : '🔴');
+            const normalizeScore = res => Math.round(res * 100);
+            const formatScore = res => {
+              const s = normalizeScore(res);
+              return `${stoplight(s)} ${s}`;
+            };
+
+            const results = JSON.parse(fs.readFileSync('./lighthouse-report/manifest.json', 'utf8'));
+            const links = JSON.parse(fs.readFileSync('./lighthouse-report/links.json', 'utf8'));
+
+            const header = [
+              '## 🚦 Lighthouse Results',
+              '| URL | Perf | A11y | Best Practices | SEO | Report |',
+              '| --- | ---- | ---- | -------------- | --- | ------ |',
+            ];
+
+            const rows = results.map(({ url, summary }) => {
+              const short = `[${new URL(url).pathname}](${url})`;
+              const perf = formatScore(summary.performance);
+              const a11y = formatScore(summary.accessibility);
+              const bp = formatScore(summary['best-practices']);
+              const seo = formatScore(summary.seo);
+              return `${short} | ${perf} | ${a11y} | ${bp} | ${seo} | [🔗](${links[url]})`;
+            });
+
+            const comment = [...header, ...rows].join('\n');
+            core.setOutput('comment', comment);
+
+      - name: 💬 Comment on PR
+        uses: actions/github-script@v7
+        with:
+          script: |
+            github.rest.issues.createComment({
+              issue_number: context.payload.pull_request.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: `${{ steps.format.outputs.comment }}`
+            });