finishEvent() takes an EventTemplate and returns an Event.

event.ts

@@ -2,6 +2,7 @@ import * as secp256k1 from '@noble/secp256k1'
 import {sha256} from '@noble/hashes/sha256'
 
 import {utf8Encoder} from './utils'
+import {getPublicKey} from './keys'
 
 /* eslint-disable no-unused-vars */
 export enum Kind {
@@ -47,6 +48,14 @@ export function getBlankEvent(): EventTemplate {
   }
 }
 
+export function finishEvent(t: EventTemplate, privateKey: string): Event {
+  let event = t as Event
+  event.pubkey = getPublicKey(privateKey)
+  event.id = getEventHash(event)
+  event.sig = signEvent(event, privateKey)
+  return event
+}
+
 export function serializeEvent(evt: Event): string {
   if (!validateEvent(evt))
     throw new Error("can't serialize event with wrong or missing properties")