feat: add lookup invoice to nwc webln provider

examples/nwc/lookup-invoice.js

@@ -0,0 +1,29 @@
+import * as crypto from "node:crypto"; // required in node.js
+global.crypto = crypto; // required in node.js
+import "websocket-polyfill"; // required in node.js
+
+import * as readline from "node:readline/promises";
+import { stdin as input, stdout as output } from "node:process";
+
+import { webln as providers } from "../../dist/index.module.js";
+
+const rl = readline.createInterface({ input, output });
+
+const nwcUrl = await rl.question(
+  "Nostr Wallet Connect URL (nostrwalletconnect://...): ",
+);
+rl.close();
+
+const webln = new providers.NostrWebLNProvider({
+  nostrWalletConnectUrl: nwcUrl,
+});
+await webln.enable();
+const response = await webln.lookupInvoice({
+  // provide one of the below
+  //invoice: 'lnbc10n1pjwxschpp5hg0pw234n9ww9q4uy25pnvu8y4jzpznysasyf7m9fka36t7fahysdqufet5xgzhv43ycn3qv4uxzmtsd3jscqzzsxqyz5vqsp5uw023qhxuxqfj69rvj9yns5gufczad5gqw4uer5cgqhw90slkavs9qyyssqvv2tw6c30ssgtpejc3zk7ns0svuj8547d8wxj0e36hltljx5a8x4qj59mk2y7qlt6qazf2j38fzc8uag3887nslxz6fe3vnyvg0f2xqqnlvcu2',
+  payment_hash: 'ba1e172a35995ce282bc22a819b3872564208a64876044fb654dbb1d2fc9edc9'
+});
+
+console.log(response);
+
+webln.close();

src/webln/NostrWeblnProvider.ts

@@ -40,6 +40,16 @@ interface GetBalanceResponse {
   budget_renewal?: string;
 }
 
+interface LookupInvoiceArgs {
+  invoice?: string;
+  payment_hash?: string;
+}
+
+interface LookupInvoiceResponse {
+  invoice: string;
+  paid: boolean;
+}
+
 interface NostrWebLNOptions {
   authorizationUrl?: string; // the URL to the NWC interface for the user to confirm the session
   relayUrl: string;
@@ -214,7 +224,7 @@ export class NostrWebLNProvider implements WebLNProvider, Nip07Provider {
   // TODO: use NIP-47 get_info call
   async getInfo(): Promise<GetInfoResponse> {
     return {
-      methods: ["getInfo", "sendPayment", "addinvoice", "getBalance"],
+      methods: ["getInfo", "sendPayment", "addinvoice", "getBalance", "lookupinvoice"],
       node: {} as WebLNNode,
       supports: ["lightning"],
       version: "NWC",
@@ -258,6 +268,7 @@ export class NostrWebLNProvider implements WebLNProvider, Nip07Provider {
   ): Promise<{ status: "OK" } | { status: "ERROR"; reason: string }> {
     throw new Error("Method not implemented.");
   }
+
   makeInvoice(args: string | number | RequestInvoiceArgs) {
     this.checkConnected();
 
@@ -283,6 +294,19 @@ export class NostrWebLNProvider implements WebLNProvider, Nip07Provider {
       (result) => ({ paymentRequest: result.invoice }),
     );
   }
+
+  lookupInvoice(args: LookupInvoiceArgs) {
+    this.checkConnected();
+
+    return this.executeNip47Request<LookupInvoiceResponse>(
+      "lookup_invoice",
+      "lookupinvoice",
+      args,
+      (result) => result.invoice !== undefined && result.paid !== undefined,
+      (result) => ({ paymentRequest: result.invoice, paid: result.paid }),
+    );
+  }
+
   request(method: RequestMethod, args?: unknown): Promise<unknown> {
     throw new Error("Method not implemented.");
   }