Hello Webpack4

ui/package.json

@@ -37,7 +37,6 @@
     "eslint-plugin-import": "^2.17.2",
     "eslint-plugin-jsx-a11y": "^6.2.1",
     "eslint-plugin-react": "^7.13.0",
-    "extract-text-webpack-plugin": "^3.0.2",
     "file-loader": "^2.0.0",
     "friendly-errors-webpack-plugin": "^1.7.0",
     "fs-extra": "^8.0.1",
@@ -52,7 +51,7 @@
     "js-yaml": "^3.13.1",
     "json-loader": "^0.5.7",
     "monaco-editor-webpack-plugin": "^1.9.0",
-    "optimize-css-assets-webpack-plugin": "^3.2.0",
+    "optimize-css-assets-webpack-plugin": "^5.0.3",
     "postcss-loader": "^3.0.0",
     "rupture": "^0.7.1",
     "style-loader": "^0.23.1",
@@ -61,7 +60,7 @@
     "through2": "^3.0.1",
     "uglifyjs-webpack-plugin": "^1.3.0",
     "vinyl-buffer": "^1.0.1",
-    "webpack": "^3.12.0",
+    "webpack": "^4.42.1",
     "yargs": "^13.2.4"
   },
   "dependencies": {
@@ -79,6 +78,7 @@
     "jquery.transit": "^0.9.12",
     "katex": "^0.10.2",
     "lodash": "^4.17.13",
+    "mini-css-extract-plugin": "^0.9.0",
     "moment": "^2.24.0",
     "normalize.css": "^8.0.1",
     "nprogress": "^0.2.0",
@@ -110,7 +110,6 @@
   "scripts": {
     "build": "node build",
     "build:production": "node build --production",
-    "build:watch": "node build --watch",
     "lint": "eslint --fix ."
   },
   "babel": {