Add format:check script

.github/workflows/ci.yml

@@ -5,6 +5,20 @@ on:
   - pull_request
 
 jobs:
+  format-check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Use Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: 16
+          cache: 'yarn'
+      - name: Install dependencies
+        run: yarn
+      - name: Format check
+        run: yarn format:check
+
   build:
     runs-on: ubuntu-latest
     steps:

.prettierignore

@@ -0,0 +1,2 @@
+# output
+dist

package.json

@@ -30,6 +30,8 @@
     "build": "tsup",
     "example:custom-properties": "ts-node ./examples/custom-properties.ts",
     "example:custom-media-queries": "ts-node ./examples/custom-media-queries.ts",
+    "format": "prettier --write .",
+    "format:check": "prettier --check .",
     "prebuild": "rimraf ./dist",
     "prepublishOnly": "npm run build",
     "test": "vitest",