feat: 🎸 Allow building and bundling of web workers in ember (#2923)

* feat: 🎸 Allow building and bundling of web workers in ember

* refactor: 💡 Cleanup code and add comments

addons/api/addon/services/sqlite-db.js

@@ -0,0 +1,46 @@
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: BUSL-1.1
+ */
+
+import Service from '@ember/service';
+import { PWBHost } from 'promise-worker-bi';
+
+export default class SqliteDbService extends Service {
+  // =attributes
+
+  // We need a handle on the original web worker to properly clean it up.
+  webWorker;
+  // This will be the worker we interact with that is wrapped by PWBHost.
+  worker;
+
+  // TODO: Actually use the name that gets passed into setup later
+  setup() {
+    if (this.worker) {
+      // If the worker already exists, we don't need to do anything.
+      return;
+    }
+
+    // In production, our JS files will be fingerprinted with am MD5 hash
+    // so we need a way to map the worker file name to be able to find it.
+    //
+    // Ember is automagically replacing any URL path with the fingerprinted
+    // asset, and this is done by broccoli-asset-rev.
+    //
+    // The problem is it's a bit finicky as seen in this issue
+    // https://github.com/ember-cli/broccoli-asset-rewrite/issues/66
+    // and will not work properly if it's part of a template string or interpolated.
+    // Therefore, we need the URL path in a string somewhere to be replaced properly.
+    this.webWorker = new Worker('/workers/web-worker.js', {
+      type: 'module',
+    });
+
+    // We use PWBHost to simplify communication so we can just send and receive
+    // messages with promises rather than having to manually set up event listeners
+    this.worker = new PWBHost(this.webWorker);
+  }
+
+  willDestroy() {
+    this.webWorker?.terminate();
+  }
+}