Add webpack loader plugin

webpack/plugins/AddWorkerEntryPointPlugin.js

@@ -0,0 +1,27 @@
+class AddWorkerEntryPointPlugin {
+  constructor(webpack, { id, entry, output }) {
+    this.webpack = webpack;
+    this.options = { id, entry, output };
+  }
+
+  apply(compiler) {
+    const webpack = this.webpack;
+    const { id, entry, output } = this.options;
+    compiler.plugin('make', (compilation, callback) => {
+      const outputOptions = {
+        filename: output,
+        publicPath: compilation.outputOptions.publicPath,
+        // HACK: globalObject is necessary to fix https://github.com/webpack/webpack/issues/6642
+        globalObject: 'this',
+      };
+      const childCompiler = compilation.createChildCompiler(id, outputOptions, [
+        new webpack.webworker.WebWorkerTemplatePlugin(),
+        new webpack.LoaderTargetPlugin('webworker'),
+        new webpack.SingleEntryPlugin(this.context, entry, 'main'),
+      ]);
+      childCompiler.runAsChild(callback);
+    });
+  }
+}
+
+module.exports = AddWorkerEntryPointPlugin;