index.js

var WebWorkerTemplatePlugin = require('webpack/lib/webworker/WebWorkerTemplatePlugin');
var SingleEntryPlugin = require('webpack/lib/SingleEntryPlugin');
var path = require('path');

var loaderUtils = require('loader-utils');
module.exports = function() {};
module.exports.pitch = function(request) {
  if (!this.webpack)
    throw new Error('Only usable with webpack');
  var callback = this.async();
  var query = loaderUtils.parseQuery(this.query);
  var outputOptions = {
    filename: '[hash].sharedworker.js',
    chunkFilename: '[id].[hash].sharedworker.js',
    namedChunkFilename: null
  };
  if (this.options && this.options.worker && this.options.worker.output) {
    for (var name in this.options.worker.output) {
      outputOptions[name] = this.options.worker.output[name];
    }
  }
  var workerCompiler = this._compilation.createChildCompiler('sharedworker', outputOptions);
  workerCompiler.apply(new WebWorkerTemplatePlugin(outputOptions));
  workerCompiler.apply(new SingleEntryPlugin(this.context, '!!' + request, 'main'));
  if (this.options && this.options.worker && this.options.worker.plugins) {
    this.options.worker.plugins.forEach(function(plugin) {
      workerCompiler.apply(plugin);
    });
  }
  var subCache = 'subcache ' + __dirname + ' ' + request;
  workerCompiler.plugin('compilation', function(compilation) {
    if (compilation.cache) {
      if (!compilation.cache[subCache])
        compilation.cache[subCache] = {};
      compilation.cache = compilation.cache[subCache];
    }
  });
  workerCompiler.runAsChild(function(err, entries, compilation) {
    if (err) return callback(err);
    if (entries[0]) {
      var workerFile = entries[0].files[0];
      var constructor = 'new SharedWorker(__webpack_public_path__ + ' + JSON.stringify(workerFile) + ', name)';
      if (query.inline) {
        constructor = 'require(' + JSON.stringify('!!' + path.join(__dirname, 'createInlineWorker.js')) + ')(' +
          JSON.stringify(compilation.assets[workerFile].source()) + ', __webpack_public_path__ + ' + JSON.stringify(workerFile) + ', name)';
      }
      return callback(null, 'module.exports = function(name) {\n\treturn ' + constructor + ';\n};');
    } else {
      return callback(null, null);
    }
  });
};