create-react-app实现antd的按需加载

按需加载antd的实现方式：

用create-react-app创建项目后，如果需要第三方的插件库，需要配置webpack配置文件，步骤如下：
1.首先运行npm run eject暴露出webpack的配置文件，项目对多出config和scripts文件夹
2.安装完antd和babel-plugin-import后，修改config目录下的webpack.config.js里面 // Process any JS outside of the app with Babel 下面，在persets后面添加

           // Process any JS outside of the app with Babel.
            // Unlike the application JS, we only compile the standard ES features.
            {
              test: /\.(js|mjs)$/,
              exclude: /@babel(?:\/|\\{1,2})runtime/,
              loader: require.resolve('babel-loader'),
              options: {
                babelrc: false,
                configFile: false,
               compact: false,
                presets: [
                  [
                    require.resolve('babel-preset-react-app/dependencies'),
                    { helpers: true },
                  ],
                ],
                plugins:[
                  ["import",{"libraryName": "antd", "style": "true"}] //此处添加
                ],
                cacheDirectory: true,
                // See #6846 for context on why cacheCompression is disabled
                cacheCompression: false,
                // Babel sourcemaps are needed for debugging into node_modules
                // code.  Without the options below, debuggers like VSCode
                // show incorrect code and set breakpoints on the wrong lines.
                sourceMaps: shouldUseSourceMap,
                inputSourceMap: shouldUseSourceMap,
              },
            },