fix: prevent bundles overwriting each other (#573)

* refactor: use target (clearer intention)

* fix: use contenthash to avoid name clashes

This lets us keep sharing any common chunks (i.e. common to the python and js evaluators) because they're stored in the same folder, but if the chunks differ at all they become separate files. Ideally, large files (like typescript) would be shared between all three evaluators, but it's not clear how to achieve that. It may not be possible

Author: ojeytonwilliams

packages/helpers/lib/index.ts

@@ -2,7 +2,9 @@ import { strip } from "./strip";
 import astHelpers from "../python/py_helpers.py";
 
 export const Explorer = async (code: string) =>
-  new (await import("./class/explorer")).Explorer(code);
+  new (
+    await import(/* webpackChunkName: "explorer" */ "./class/explorer")
+  ).Explorer(code);
 
 declare global {
   var IS_REACT_ACT_ENVIRONMENT: boolean;

webpack.config.js

@@ -139,8 +139,9 @@ const testRunnerConfig =
         path: isDev
           ? __dirname + "/__fixtures__/dist"
           : __dirname + "/dist/test-runner",
-        ...(isWorker && { chunkLoading: "import-scripts" }),
+        chunkFilename: "[name].[contenthash].js",
       },
+      target: isWorker ? "webworker" : "web",
       module: {
         rules: [
           {