Add coverage checking with c8 (#34)

Author: davidjgoss

.github/workflows/test.yaml

@@ -29,6 +29,19 @@ jobs:
       - run: npm ci
       - run: npm run lint
       - run: npm test
+
+  coverage:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 23.x
+      - run: npm ci
+      - run: npm run build
+      - run: npm run coverage:check
+
   exports:
     runs-on: ubuntu-latest
 

.gitignore

@@ -1,4 +1,5 @@
 _site
+coverage
 lib
 node_modules
 tmp