1 files changed, 18 insertions, 0 deletions
diff --git a/spec/frontend/__helpers__/web_worker_transformer.js b/spec/frontend/__helpers__/web_worker_transformer.js
new file mode 100644
index 00000000000..5b2f7d77947
--- /dev/null
+++ b/spec/frontend/__helpers__/web_worker_transformer.js
@@ -0,0 +1,18 @@
+/* eslint-disable import/no-commonjs */
+const babelJestTransformer = require('babel-jest');
+
+// This Jest will transform the code of a WebWorker module into a FakeWebWorker subclass.
+// This is meant to mirror Webpack's [`worker-loader`][1].
+// [1]: https://webpack.js.org/loaders/worker-loader/
+module.exports = {
+  process: (contentArg, filename, ...args) => {
+    const { code: content } = babelJestTransformer.process(contentArg, filename, ...args);
+
+    return `const { FakeWebWorker } = require("helpers/web_worker_fake");
+    module.exports = class JestTransformedWorker extends FakeWebWorker {
+      constructor() {
+        super(${JSON.stringify(filename)}, ${JSON.stringify(content)});
+      }
+    };`;
+  },
+};