Add code coverage

Author: dhensby

.github/workflows/nodejs.yml

@@ -28,7 +28,20 @@ jobs:
           cache: 'npm'
       - run: npm ci
       - run: npm run lint
-
+#  coverage:
+#    name: Coverage check
+#    runs-on: ubuntu-latest
+#    steps:
+#      - uses: actions/checkout@v2
+#      - name: Code coverage
+#        uses: actions/setup-node@v2
+#        with:
+#          node-version: 12.x
+#          cache: 'npm'
+#      - run: npm ci
+#      - run: npm run test:coverage
+#      - name: Code Coverage Report
+#        uses: romeovs/lcov-reporter-action@v0.2.11
   tests:
     name: Unit tests
     runs-on: ubuntu-latest
@@ -46,4 +59,4 @@ jobs:
           node-version: ${{ matrix.node-version }}
           cache: 'npm'
       - run: npm ci
-      - run: npm test
+      - run: npm run test:coverage

.gitignore

@@ -1,2 +1,4 @@
 /lib/
 /node_modules/
+/.nyc_output/
+/coverage/

.nycrc

@@ -0,0 +1,5 @@
+{
+    "all": true,
+    "extension": [".ts"],
+    "include": ["src/**"]
+}