Add gts for TypeScript style check (#10)

- Install gts
- Add a GitHub action for TypeScript style check
- Fix existing codes to align with the style guide

.github/workflows/style-check.yml

@@ -10,3 +10,14 @@ jobs:
           python-version: '3.7'
       - run: python -m pip install --upgrade yapf
       - run: yapf --diff --recursive budoux tests
+  typescript-style-check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: '16'
+      - run: npm install
+        working-directory: ./javascript
+      - run: npm run lint
+        working-directory: ./javascript

javascript/.eslintignore

@@ -0,0 +1,3 @@
+dist
+module
+src/data

javascript/.eslintrc.json

@@ -0,0 +1,8 @@
+{
+  "extends": "./node_modules/gts/",
+  "rules": {
+    "node/no-unpublished-import": ["error", {
+      "allowModules": ["jasmine"]
+    }]
+  }
+}

javascript/.prettierrc.js

@@ -0,0 +1,3 @@
+module.exports = {
+  ...require('gts/.prettierrc.json')
+}