ERROR in ./src/index.js
Module not found: Error: Can't resolve 'babel-runtime/core-js/object/get-prototype-of' in 'E:\Code\web\web\webpack-20190318\src'
 @ ./src/index.js 3:22-78
 @ multi ./node_modules/_webpack-dev-server@3.2.1@webpack-dev-server/client?http://localhost:8084 (webpack)/hot/dev-server.js ./src

ERROR in ./src/index.js
Module not found: Error: Can't resolve 'babel-runtime/helpers/classCallCheck' in 'E:\Code\web\web\webpack-20190318\src'
 @ ./src/index.js 7:23-70
 @ multi ./node_modules/_webpack-dev-server@3.2.1@webpack-dev-server/client?http://localhost:8084 (webpack)/hot/dev-server.js ./src

ERROR in ./src/index.js
Module not found: Error: Can't resolve 'babel-runtime/helpers/createClass' in 'E:\Code\web\web\webpack-20190318\src'
 @ ./src/index.js 11:20-64
 @ multi ./node_modules/_webpack-dev-server@3.2.1@webpack-dev-server/client?http://localhost:8084 (webpack)/hot/dev-server.js ./src

ERROR in ./src/index.js
 @ ./src/index.js 19:17-58
 @ multi ./node_modules/_webpack-dev-server@3.2.1@webpack-dev-server/client?http://localhost:8084 (webpack)/hot/dev-server.js ./src

Module not found: Error: Can't resolve 'babel-runtime/helpers/possibleConstructorReturn' in 'E:\Code\web\web\webpack-20190318\src'
 @ ./src/index.js 15:34-92
 @ multi ./node_modules/_webpack-dev-server@3.2.1@webpack-dev-server/client?http://localhost:8084 (webpack)/hot/dev-server.js ./src

报此类的错误，重新安装babel-runtime即可

简写

npm i babel-runtime -D

全写

npm install babel-runtime --save-dev