Add 'yarn lint' command and run it in GH actions (#517)

* Add 'yarn lint' command and run it in GH actions

* Move linting to own workflow

* Remove linting from build-workflow

* Solve linting warnings

Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>

Co-authored-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>

.github/workflows/build.yml

@@ -1,4 +1,4 @@
-name: lint and build
+name: test, build
 
 on:
   push:
@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         node: ['12', '14']
-    name: Test with NodeJS ${{ matrix.node }}
+    name: Test and build with NodeJS ${{ matrix.node }}
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2

.github/workflows/lint.yml

@@ -0,0 +1,28 @@
+name: lint
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    name: Lints all .ts and .tsx files
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+      - name: Cache node_modules
+        uses: actions/cache@v1.1.0
+        with:
+          path: node_modules
+          key: node_modules
+      - name: Set up NodeJS
+        uses: actions/setup-node@v1
+        with:
+          node-version: 14
+      - name: Install dependencies
+        run: yarn install
+      - name: Lint code
+        run: yarn lint