👷 Add CI pipeline for package publishing

.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+insert_final_newline = true
+max_line_length = 100
+trim_trailing_whitespace = true

.github/workflows/publish.yml

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+name: Build and publish npm package
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - '*'
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    name: Create build
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v3
+        with:
+          node-version-file: '.nvmrc'
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build library
+        run: |
+          npm run build
+
+      - name: Store build artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: build
+          path: build/
+          retention-days: 1
+
+  publish:
+    name: Publish the NPM package
+    runs-on: ubuntu-latest
+    needs:
+      - build
+
+    # do not publish in forks or non-tag pushes
+    if: startsWith(github.ref, 'refs/tags/') && github.repository_owner == 'open-formulieren'
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v3
+        with:
+          node-version-file: '.nvmrc'
+          cache: npm
+          registry-url: 'https://registry.npmjs.org'
+          scope: '@open-formulieren'
+
+      - name: Download build artifact
+        uses: actions/download-artifact@v3
+        with:
+          name: build
+          path: build/
+
+      - name: Publish package to NPM
+        run: |
+          # Strip git ref prefix from version
+          VERSION=$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')
+
+          npm publish --access public --new-version=$VERSION
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}