add NIP-78 interface

ndk/src/app-settings/index.ts

@@ -0,0 +1,75 @@
+import { NDKKind } from "../events/kinds";
+import { NDKEvent, type NostrEvent } from "../events/index.js";
+import type { NDK } from "../ndk";
+import { NDKRelaySet } from "../relay/sets";
+
+/**
+ * Implements NIP-78 App Settings
+ * 
+ * @example
+ * const appSettings = new NDKAppSettings(ndk)
+ * appSettings.appName = "My App";
+ * appSettings.set("my_key", "my_value");
+ * await appSettings.save();
+ * 
+ * @example
+ * const appSettings = NDKAppSettings.from(event);
+ * appSettings.appName = "My App";
+ * console.log(appSettings.get("my_key"));
+ * 
+ * @group Kind Wrapper
+ * 
+ * @see https://github.com/nostr-protocol/nips/blob/master/78.md
+ */
+export class NDKAppSettings extends NDKEvent {
+    public appName: string | undefined;
+    public settings: Record<string, unknown> = {};
+
+    constructor(ndk: NDK | undefined, rawEvent?: NostrEvent | NDKEvent) {
+        super(ndk, rawEvent);
+        this.kind ??= NDKKind.AppSpecificData;
+        this.dTag ??= this.appName;
+
+        if (this.content.length > 0) {
+            try {
+                this.settings = JSON.parse(this.content);
+            } catch (error) {
+                console.error("Error parsing app settings", error);
+            }
+        }
+    }
+
+    static from(event: NDKEvent) {
+        return new NDKAppSettings(event.ndk, event);
+    }
+
+    /**
+     * Set a value for a given key.
+     * 
+     * @param key 
+     * @param value 
+     */
+    set(key: string, value: unknown) {
+        this.settings[key] = value;
+    }
+
+    /**
+     * Get a value for a given key.
+     * 
+     * @param key 
+     * @returns 
+     */
+    get(key: string) {
+        return this.settings[key];
+    }
+
+    public async publishReplaceable(
+        relaySet?: NDKRelaySet,
+        timeoutMs?: number,
+        requiredRelayCount?: number
+    ) {
+        this.content = JSON.stringify(this.settings);
+
+        return super.publishReplaceable(relaySet, timeoutMs, requiredRelayCount);
+    }
+}

ndk/src/index.ts

@@ -30,6 +30,8 @@ export * from "./events/kinds/simple-group/index.js";
 export * from "./events/kinds/simple-group/metadata.js";
 export * from "./events/kinds/simple-group/member-list.js";
 
+export * from "./app-settings/index.js";
+
 export * from "./relay/index.js";
 export * from "./relay/auth-policies.js";
 export * from "./relay/sets/index.js";