feat: 💨

src/lib/timeline.ts

@@ -0,0 +1,47 @@
+import { NostrEvent } from 'nostr-tools'
+import { compareEvents } from './event'
+
+export function mergeTimelines(timelines: NostrEvent[][], limit: number) {
+  if (timelines.length === 0) return []
+  if (timelines.length === 1) return [...timelines[0]]
+  return timelines.reduce((merged, current) => _mergeTimelines(merged, current, limit), [])
+}
+
+function _mergeTimelines(a: NostrEvent[], b: NostrEvent[], limit: number): NostrEvent[] {
+  if (a.length === 0) return [...b]
+  if (b.length === 0) return [...a]
+
+  const result: NostrEvent[] = []
+  let i = 0
+  let j = 0
+  while (i < a.length && j < b.length) {
+    const cmp = compareEvents(a[i], b[j])
+    if (cmp > 0) {
+      result.push(a[i])
+      i++
+    } else if (cmp < 0) {
+      result.push(b[j])
+      j++
+    } else {
+      result.push(a[i])
+      i++
+      j++
+    }
+  }
+
+  if (result.length >= limit) {
+    return result
+  }
+
+  while (i < a.length && result.length < limit) {
+    result.push(a[i])
+    i++
+  }
+
+  while (j < b.length && result.length < limit) {
+    result.push(b[j])
+    j++
+  }
+
+  return result
+}