CI for linting and local dev utils (WebDevCaptain-Lab#11)

* Install lint-staged and setup husky with linters

Run linter and formatter in a pre-commit hook with lint-staged configuration.

* Update add module functionality to allow multiple numbers as args.

Add a lint job in CI workflow.

.github/workflows/ci.yml

@@ -17,6 +17,30 @@ on:
   workflow_dispatch:
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Clone repo
+        uses: actions/checkout@v4
+
+      - name: Install NodeJS
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22.12.0
+
+      - name: Cache npm dependencies
+        uses: actions/cache@v4
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run linter
+        run: npm run lint
+
   test:
     runs-on: ubuntu-latest
 

.husky/pre-commit

@@ -1 +1 @@
-npm test
+npx lint-staged && npm test