fix: GeoJSON export (#1283)

* fix: use global vars instead of window.

* feat: add GitHub Actions workflow for unit tests

* fix: change mapCoordinates declaration from let to var for compatibility

.github/workflows/unit-tests.yml

@@ -0,0 +1,17 @@
+name: Unit Tests
+on:
+  pull_request:
+    branches: [ master ]
+jobs:
+  test:
+    timeout-minutes: 60
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v5
+    - uses: actions/setup-node@v5
+      with:
+        node-version: '24'
+    - name: Install dependencies
+      run: npm ci
+    - name: Run Unit tests
+      run: npm run test