暴露配置文件

create-react-app 生成的项目文，看不到 webpack 相关的配置文件，需要先暴露出来，使用如下命令即可

npm run eject

安装 less-loader 和 less

npm install less-loader less --save-dev

修改 webpack 配置

webpack.config.js

在 exclude 数组中增加 /\.less$/

{
  loader: require.resolve('file-loader'),
  exclude: [/\.(js|mjs|jsx|ts|tsx)$/, /\.html$/, /\.json$/, /\.less$/],
  options: {
    name: 'static/media/[name].[hash:8].[ext]',
  }
}

在 oneOf 数组末尾添加下面对象

const autoprefixer = require('autoprefixer');

{
  test: /\.(css|less)$/,
  use: [
    require.resolve('style-loader'),
    {
      loader: require.resolve('css-loader'),
      options: {
        importLoaders: 1
      }
    },
    {
      loader: require.resolve('postcss-loader'),
      options: {
        // Necessary for external CSS imports to work
        // https://github.com/facebookincubator/create-react-app/issues/2677
        ident: 'postcss',
        plugins: () => [
          require('postcss-flexbugs-fixes'),
          autoprefixer({
            browsers: [
              '>1%',
              'last 4 versions',
              'Firefox ESR',
              'not ie < 9', // React doesn't support IE8 anyway
            ],
            flexbox: 'no-2009'
          })
        ]
      }
    },
    {
      loader: require.resolve('less-loader') // compiles Less to CSS
    }
  ]
}