修改babel配置

.babelrc

           "browsers": ["> 1%", "last 2 versions", "ie >= 10"]
         }
       }
-    ],
-    "@babel/preset-stage-2"
+    ]
   ],
-  "plugins": ["@babel/plugin-transform-runtime"]
+  "plugins": ["@babel/plugin-transform-runtime","@babel/plugin-proposal-class-properties"]
 }

package.json

   },
   "devDependencies": {
     "@babel/core": "^7.4.0",
+    "@babel/plugin-proposal-class-properties": "^7.12.1",
     "@babel/plugin-transform-runtime": "^7.4.0",
     "@babel/polyfill": "^7.4.0",
     "@babel/preset-env": "^7.4.2",
-    "@babel/preset-stage-2": "^7.0.0",
     "babel-eslint": "^10.0.1",
     "babel-loader": "^8.0.5",
     "copy-webpack-plugin": "^5.0.2",
     "css-loader": "^2.1.1",
     "eslint": "^5.15.3",
     "eslint-config-prettier": "^4.1.0",
-    "eslint-plugin-import": "^2.16.0",
+    "eslint-plugin-import": "^2.1.0",
     "eslint-plugin-node": "^8.0.1",
     "eslint-plugin-prettier": "^3.0.1",
     "eslint-plugin-promise": "^4.0.1",

yarn.lock

     "@babel/types" "^7.4.4"
     esutils "^2.0.2"
 
-"@babel/preset-stage-2@^7.0.0":
-  version "7.8.3"
-  resolved "https://registry.yarnpkg.com/@babel/preset-stage-2/-/preset-stage-2-7.8.3.tgz#35055d2d22457706048deb5599c487943c05c241"
-  integrity sha512-dStnEQgejNYIHFNACdDCigK4BF7wgW6Zahv9Dc2un7rGjbeVtZhBfR3sy0I7ZJOhBexkFxVdMZ5hqmll7BFShw==
-
 "@babel/runtime@^7.8.4":
   version "7.12.5"
   resolved "https://registry.yarnpkg.com/@babel/runtime/-/runtime-7.12.5.tgz#410e7e487441e1b360c29be715d870d9b985882e"
     lodash.uniq "^4.5.0"
 
 caniuse-lite@^1.0.0, caniuse-lite@^1.0.30001157:
-  version "1.0.30001157"
-  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30001157.tgz#2d11aaeb239b340bc1aa730eca18a37fdb07a9ab"
-  integrity sha512-gOerH9Wz2IRZ2ZPdMfBvyOi3cjaz4O4dgNwPGzx8EhqAs4+2IL/O+fJsbt+znSigujoZG8bVcIAUM/I/E5K3MA==
+  version "1.0.30001158"
+  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30001158.tgz#fce86d321369603c2bc855ee0e901a7f49f8310b"
+  integrity sha512-s5loVYY+yKpuVA3HyW8BarzrtJvwHReuzugQXlv1iR3LKSReoFXRm86mT6hT7PEF5RxW+XQZg+6nYjlywYzQ+g==
 
 caseless@~0.12.0:
   version "0.12.0"
     postcss "^7.0.0"
 
 csso@^4.0.2:
-  version "4.1.0"
-  resolved "https://registry.yarnpkg.com/csso/-/csso-4.1.0.tgz#1d31193efa99b87aa6bad6c0cef155e543d09e8b"
-  integrity sha512-h+6w/W1WqXaJA4tb1dk7r5tVbOm97MsKxzwnvOR04UQ6GILroryjMWu3pmCCtL2mLaEStQ0fZgeGiy99mo7iyg==
+  version "4.1.1"
+  resolved "https://registry.yarnpkg.com/csso/-/csso-4.1.1.tgz#e0cb02d6eb3af1df719222048e4359efd662af13"
+  integrity sha512-Rvq+e1e0TFB8E8X+8MQjHSY6vtol45s5gxtLI/018UsAn2IBMmwNEZRM/h+HVnAJRHjasLIKKUO3uvoMM28LvA==
   dependencies:
     css-tree "^1.0.0"
 
     eslint-utils "^1.4.2"
     regexpp "^2.0.1"
 
-eslint-plugin-import@^2.16.0:
+eslint-plugin-import@^2.1.0:
   version "2.22.1"
   resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.22.1.tgz#0896c7e6a0cf44109a2d97b95903c2bb689d7702"
   integrity sha512-8K7JjINHOpH64ozkAhpT3sd+FswIZTfMZTjdx052pnWrgRCVfp8op9tbjpAk3DdUeI/Ba4C8OjdC0r90erHEOw==