babel升级问题

一、webpack4.x

使用babel7.x 版本

使用：babel-loader @babel/core @babel/preset-env @babel/preset-react @babel/plugin-proposal-class-properties @babel/plugin-transform-runtime 等包

npm install babel-loader @babel/core @babel/preset-env @babel/preset-react @babel/plugin-proposal-class-properties @babel/plugin-transform-runtime -D

配置：

{
    "presets": ["@babel/preset-env", "@babel/react"],
    "plugins": [
                "@babel/plugin-proposal-class-properties",
                "@babel/plugin-transform-runtime" 
               ]
}

二、继续使用babel6.x

使用：babel-loader@7.1.5 babel-core babel-preset-env  babel-preset-react  babel-plugin-transform-runtime 等包

npm install babel-loader@7 babel-core babel-preset-env  babel-preset-react  babel-plugin-transform-runtime -D

配置：

{
    "presets": ["env", "react"],
    "plugins": ["transform-runtime"]                               
               
}