Add auto-formatting

.travis.yml

@@ -3,6 +3,7 @@ node_js:
   - "12"
 script:
   - npm run eslint
+  - npm run prettier-check
   - npm run test -- --failTaskOnError --suppressPassed
 
 after_success:

package.json

@@ -50,6 +50,11 @@
     "prettier": "2.3.2",
     "pretty-quick": "^3.1.1"
   },
+  "husky": {
+    "hooks": {
+      "pre-commit": "eslint && pretty-quick --staged"
+    }
+  },
   "scripts": {
     "jsdoc": "jsdoc ./lib -R ./README.md -d doc",
     "eslint": "eslint \"./**/*.js\" --cache --quiet",