Add GitHub Action to publish map-styles to npm (#61)

* Add GitHub Action to publish map-styles to npm

* Testing the release action with --dry-run

* Validate first the changes

* Validate on push only to avoid duplicate runs

* Test dry-run with OIDC

* Simplify validate (OIDC already verified)

Author: Rub21

.github/workflows/release.yml

@@ -0,0 +1,64 @@
+name: Release to npm
+
+on:
+  workflow_dispatch:
+    inputs:
+      bump:
+        description: 'Version bump'
+        type: choice
+        options:
+          - patch
+          - minor
+          - major
+        default: patch
+
+concurrency:
+  group: release
+  cancel-in-progress: false
+
+jobs:
+  release:
+    if: github.ref_name == 'staging'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      id-token: write
+    steps:
+      - name: Verify staging branch
+        run: |
+          if [ "${{ github.ref_name }}" != "staging" ]; then
+            echo "::error::Releases can only be triggered from the 'staging' branch (got: ${{ github.ref_name }})"
+            exit 1
+          fi
+
+      - uses: actions/checkout@v4
+        with:
+          ref: staging
+          fetch-depth: 0
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: '.nvmrc'
+          registry-url: 'https://registry.npmjs.org'
+
+      - run: npm ci
+
+      - name: Configure git identity
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+
+      - name: Bump version, rebuild /dist, commit and tag
+        run: |
+          NEW_VERSION=$(npm version ${{ inputs.bump }} --no-git-tag-version)
+          NEW_VERSION="${NEW_VERSION#v}"
+          npm run build
+          git add package.json package-lock.json dist/
+          git commit -m "Packaging ${NEW_VERSION} with rebuilt /dist"
+          git tag "v${NEW_VERSION}"
+
+      - name: Push to GitHub
+        run: git push origin staging --follow-tags
+
+      - name: Publish to npm with provenance
+        run: npm publish --provenance --access public

.github/workflows/validate.yml

@@ -0,0 +1,25 @@
+name: Validate build
+
+on:
+  push:
+    branches-ignore:
+      - staging
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: '.nvmrc'
+          registry-url: 'https://registry.npmjs.org'
+
+      - run: npm ci
+
+      - name: Build /dist
+        run: npm run build
+
+      - name: Validate npm package (dry-run)
+        run: npm publish --dry-run

README.md

@@ -70,6 +70,8 @@ Miscellaneous notes:
 
 ## Versioning and publishing to npm
 
+> Releases can be automated via [Actions → "Release to npm"](https://github.com/OpenHistoricalMap/map-styles/actions/workflows/release.yml) — click **Run workflow**, choose `patch` / `minor` / `major`, and it builds `/dist`, commits, tags, and publishes with provenance via npm Trusted Publishers (no token required). Manual steps below remain as a fallback.
+
 1. increment the version in `package.json`, e.g., `0.9.7`
 1. commit your style changes, including `/dist/*` & `package.json`, push to GitHub, and [create a corresponding release](https://github.com/OpenHistoricalMap/map-styles/releases/new), e.g., `v0.9.7`
 1. publish to npm using `npm publish`