text: import fs from 'fs';
  import path from 'path';
  import loaderUtils from 'loader-utils';
  import NodeTemplatePlugin from 'webpack/lib/node/NodeTemplatePlugin';
  import NodeTargetPlugin from 'webpack/lib/node/NodeTargetPlugin';
  import LibraryTemplatePlugin from 'webpack/lib/LibraryTemplatePlugin';
  import SingleEntryPlugin from 'webpack/lib/SingleEntryPlugin';
  import LimitChunkCountPlugin from 'webpack/lib/optimize/LimitChunkCountPlugin';
  
  const NS = path.dirname(fs.realpathSync(__filename));
  
  export default source => source;
  
  export function pitch(request) {
    const query = loaderUtils.getOptions(this) || {};
    let loaders = this.loaders.slice(this.loaderIndex + 1);
    // We already in child compiler, return empty bundle
    if (this[NS] === undefined) { // eslint-disable-line no-undefined
      throw new Error(
        '"extract-text-webpack-plugin" loader is used without the corresponding plugin, ' +
        'refer to https://github.com/webpack/extract-text-webpack-plugin for the usage example',
      );
    } else if (this[NS] === false) {
      return '';
    } else if (this[NS](null, query)) {
      if (query.omit) {
        this.loaderIndex += +query.omit + 1;
        request = request.split('!').slice(+query.omit).join('!');
        loaders = loaders.slice(+query.omit);
      }
      let resultSource;
      if (query.remove) {
        resultSource = '// removed by extract-text-webpack-plugin';
      } else {
        resultSource = undefined; // eslint-disable-line no-undefined
      }
  
      const childFilename = 'extract-text-webpack-plugin-output-filename'; // eslint-disable-line no-path-concat
      const publicPath = typeof query.publicPath === 'string' ? query.publicPath : this._compilation.outputOptions.publicPath;
      const outputOptions = {
        filename: childFilename,
        publicPath,
      };
      const childCompiler = this._compilation.createChildCompiler(`extract-text-webpack-plugin ${NS} ${request}`, outputOptions);
      childCompiler.apply(new NodeTemplatePlugin(outputOptions));
      childCompiler.apply(new LibraryTemplatePlugin(null, 'commonjs2'));
      childCompiler.apply(new NodeTargetPlugin());
      childCompiler.apply(new SingleEntryPlugin(this.context, `!!${request}`));
      childCompiler.apply(new LimitChunkCountPlugin({ maxChunks: 1 }));
      // We set loaderContext[NS] = false to indicate we already in
      // a child compiler so we don't spawn another child compilers from there.
      childCompiler.plugin('this-compilation', (compilation) => {
        compilation.plugin('normal-module-loader', (loaderContext, module) => {
          loaderContext[NS] = false;
          if (module.request === request) {
            module.loaders = loaders.map((loader) => {
              return ({
                loader: loader.path,
                options: loader.options,
              });
            });
          }
        });
      });
  
      let source;
      childCompiler.plugin('after-compile', (compilation, callback) => {
        source = compilation.assets[childFilename] && compilation.assets[childFilename].source();
  
        // Remove all chunk assets
        compilation.chunks.forEach((chunk) => {
          chunk.files.forEach((file) => {
            delete compilation.assets[file];
          });
        });
  
        callback();
      });
      const callback = this.async();
      childCompiler.runAsChild((err, entries, compilation) => {
        if (err) return callback(err);
  
        if (compilation.errors.length > 0) {
          return callback(compilation.errors[0]);
        }
        compilation.fileDependencies.forEach((dep) => {
          this.addDependency(dep);
        }, this);
        compilation.contextDependencies.forEach((dep) => {
          this.addContextDependency(dep);
        }, this);
        if (!source) {
          return callback(new Error("Didn't get a result from child compiler"));
        }
        try {
          let text = this.exec(source, request);
          if (typeof text === 'string') {
            text = [[compilation.entries[0].identifier(), text]];
          } else {
            text.forEach((item) => {
              const id = item[0];
              compilation.modules.forEach((module) => {
                if (module.id === id) { item[0] = module.identifier(); }
              });
            });
          }
          this[NS](text, query);
          if (text.locals && typeof resultSource !== 'undefined') {
            resultSource += `\nmodule.exports = ${JSON.stringify(text.locals)};`;
          }
        } catch (e) {
          return callback(e);
        }
        if (resultSource) { callback(null, resultSource); } else { callback(); }
      });
    }
  }
  