Add Prettier and Husky

package.json

@@ -5,7 +5,11 @@
   "devDependencies": {
     "cross-env": "^5.2.0",
     "css-loader": "^2.1.1",
+    "husky": "^4.3.0",
+    "lint-staged": "^10.5.2",
     "mini-css-extract-plugin": "^0.6.0",
+    "prettier": "^2.2.1",
+    "prettier-plugin-svelte": "^1.4.1",
     "serve": "^11.0.0",
     "style-loader": "^0.23.1",
     "svelte": "^3.0.0",
@@ -17,7 +21,8 @@
   "scripts": {
     "release": "cross-env NODE_ENV=production webpack -p",
     "build": "cross-env NODE_ENV=production webpack",
-    "dev": "webpack-dev-server --content-base docs"
+    "dev": "webpack-dev-server --content-base docs",
+    "pretty": "prettier --write ./src/*"
   },
   "dependencies": {
     "mermaid": "8.8.4",
@@ -28,5 +33,13 @@
     "monaco-editor": "0.18.1",
     "svelte-routing": "^1.4.0",
     "svelte-spa-router": "^1.3.0"
+  },
+  "husky": {
+    "hooks": {
+      "pre-commit": "lint-staged"
+    }
+  },
+  "lint-staged": {
+    "*.{ts,svelte,js,css,md}": "prettier --plugin-search-dir=. --write"
   }
 }