Get rid of domain module, allow app to override default event type

packages/util/src/Encryptable.ts

@@ -0,0 +1,43 @@
+import type {EventContent, CustomEvent} from './Events'
+
+export type Encrypt = (x: string) => Promise<string>
+
+export type DecryptedEvent = CustomEvent & {
+  plaintext: Partial<EventContent>
+}
+
+export const asDecryptedEvent = (event: CustomEvent, plaintext: Partial<EventContent>) =>
+  ({...event, plaintext}) as DecryptedEvent
+
+export class Encryptable<E extends Partial<EventContent>> {
+  constructor(readonly event: E, readonly updates: E) {}
+
+  async reconcile(encrypt: Encrypt) {
+    const encryptContent = () => {
+      if (!this.updates.content) return null
+
+      return encrypt(this.updates.content)
+    }
+
+    const encryptTags = () => {
+      if (!this.updates.tags) return null
+
+      return Promise.all(
+        this.updates.tags.map(async tag => {
+          tag[1] = await encrypt(tag[1])
+
+          return tag
+        })
+      )
+    }
+
+    const [content, tags] = await Promise.all([encryptContent(), encryptTags()])
+
+    // Updates are optional. If not provided, fall back to the event's content and tags.
+    return {
+      ...this.event,
+      tags: tags || this.event.tags || [],
+      content: content || this.event.content || "",
+    }
+  }
+}