Add stable sortEvents function

core.test.ts

@@ -0,0 +1,19 @@
+import { test, expect } from 'bun:test'
+
+import { sortEvents } from './core.ts'
+
+test('sortEvents', () => {
+  const events = [
+    { id: 'abc123', pubkey: 'key1', created_at: 1610000000, kind: 1, tags: [], content: 'Hello', sig: 'sig1' },
+    { id: 'abc124', pubkey: 'key2', created_at: 1620000000, kind: 1, tags: [], content: 'World', sig: 'sig2' },
+    { id: 'abc125', pubkey: 'key3', created_at: 1620000000, kind: 1, tags: [], content: '!', sig: 'sig3' },
+  ]
+
+  const sortedEvents = sortEvents(events)
+
+  expect(sortedEvents).toEqual([
+    { id: 'abc124', pubkey: 'key2', created_at: 1620000000, kind: 1, tags: [], content: 'World', sig: 'sig2' },
+    { id: 'abc125', pubkey: 'key3', created_at: 1620000000, kind: 1, tags: [], content: '!', sig: 'sig3' },
+    { id: 'abc123', pubkey: 'key1', created_at: 1610000000, kind: 1, tags: [], content: 'Hello', sig: 'sig1' },
+  ])
+})

core.ts

@@ -49,3 +49,17 @@ export function validateEvent<T>(event: T): event is T & UnsignedEvent {
 
   return true
 }
+
+/**
+ * Sort events in reverse-chronological order by the `created_at` timestamp,
+ * and then by the event `id` (lexicographically) in case of ties.
+ * This mutates the array.
+ */
+export function sortEvents(events: Event[]): Event[] {
+  return events.sort((a: NostrEvent, b: NostrEvent): number => {
+    if (a.created_at !== b.created_at) {
+      return b.created_at - a.created_at
+    }
+    return a.id.localeCompare(b.id)
+  })
+}