implement npub cache singleton

src/lib/utils/nostrUtils.ts

@@ -1,14 +1,12 @@
 import { get } from 'svelte/store';
 import { nip19 } from 'nostr-tools';
 import { ndkInstance } from '$lib/ndk';
+import { npubCache } from './npubCache';
 
 // Regular expressions for Nostr identifiers - match the entire identifier including any prefix
 export const NOSTR_PROFILE_REGEX = /(?<![\w/])((nostr:)?(npub|nprofile)[a-zA-Z0-9]{20,})(?![\w/])/g;
 export const NOSTR_NOTE_REGEX = /(?<![\w/])((nostr:)?(note|nevent|naddr)[a-zA-Z0-9]{20,})(?![\w/])/g;
 
-// Cache for npub metadata
-const npubCache = new Map<string, {name?: string, displayName?: string}>();
-
 /**
  * HTML escape a string
  */

src/lib/utils/npubCache.ts

@@ -0,0 +1,23 @@
+export type NpubMetadata = { name?: string; displayName?: string };
+
+class NpubCache {
+  private cache: Record<string, NpubMetadata> = {};
+
+  get(key: string): NpubMetadata | undefined {
+    return this.cache[key];
+  }
+
+  set(key: string, value: NpubMetadata): void {
+    this.cache[key] = value;
+  }
+
+  has(key: string): boolean {
+    return key in this.cache;
+  }
+
+  getAll(): Record<string, NpubMetadata> {
+    return { ...this.cache };
+  }
+}
+
+export const npubCache = new NpubCache();