新人求助。。React项目中无法引用less文件

#1

报错如图

//webpack.config.dev.js

{
            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
              }
            ],
      }

//webpack.config.prod.js

{
            // modify
            test: /\.(css|less)$/,
            loader: ExtractTextPlugin.extract(
              Object.assign(
                {
                  fallback: {
                    loader: require.resolve('style-loader'),
                    options: {
                      hmr: false,
                    },
                  },
                  use: [
                    {
                      loader: require.resolve('css-loader'),
                      options: {
                        importLoaders: 1,
                        minimize: true,
                        sourceMap: shouldUseSourceMap,
                      },
                    },
                    {
                      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',
                          }),
                        ],
                      },
                    },
                    {
                      //add
                      loader: require.resolve('less-loader'),
                    }
                  ],
                },
                extractTextPluginOptions
              )
            ),
            // Note: this won't work without `new ExtractTextPlugin()` in `plugins`.
          },