优化

package.json

@@ -23,6 +23,8 @@
     "vuex": "^3.6.2"
   },
   "devDependencies": {
+    "has-bigints": "^1.0.0",
+    "webpack-dev-server": "^2.9.1",
     "amfe-flexible": "^2.2.1",
     "autoprefixer": "^7.1.2",
     "babel-core": "^6.22.1",
@@ -60,7 +62,6 @@
     "vue-template-compiler": "^2.5.2",
     "webpack": "^3.6.0",
     "webpack-bundle-analyzer": "^2.9.0",
-    "webpack-dev-server": "^2.9.1",
     "webpack-merge": "^4.1.0"
   },
   "engines": {
@@ -72,4 +73,4 @@
     "last 2 versions",
     "not ie <= 8"
   ]
-}
+}