fix(payments): surface payment preimage on send result [AMB-2789]

packages/payments/src/node/lit.ts

@@ -48,6 +48,7 @@ export async function sendAssetPayment(params: SendAssetPaymentParams): Promise<
         terminal = {
           status: result.status,
           paymentHash: result.payment_hash,
+          paymentPreimage: result.payment_preimage,
           feeSat: result.fee_sat,
           failureReason: result.failure_reason,
         };

packages/payments/src/node/lnd.test.ts

@@ -38,7 +38,14 @@ describe('sendLndPayment', () => {
     const { host, lastMacaroonHeader } = await startServer((_req, res) =>
       writeLines(res, [
         { result: { status: 'IN_FLIGHT' } },
-        { result: { status: 'SUCCEEDED', payment_hash: 'abc', fee_sat: '3' } },
+        {
+          result: {
+            status: 'SUCCEEDED',
+            payment_hash: 'abc',
+            payment_preimage: 'def',
+            fee_sat: '3',
+          },
+        },
       ]),
     );
 
@@ -54,6 +61,7 @@ describe('sendLndPayment', () => {
     assert.deepEqual(result, {
       status: 'SUCCEEDED',
       paymentHash: 'abc',
+      paymentPreimage: 'def',
       feeSat: '3',
       failureReason: undefined,
     });

packages/payments/src/node/lnd.ts

@@ -42,6 +42,7 @@ export async function sendLndPayment(params: SendLndPaymentParams): Promise<Node
         terminal = {
           status: result.status,
           paymentHash: result.payment_hash,
+          paymentPreimage: result.payment_preimage,
           feeSat: result.fee_sat,
           failureReason: result.failure_reason,
         };

packages/payments/src/node/types.ts

@@ -13,6 +13,7 @@ export interface SendLndPaymentBody {
 export interface LndPaymentUpdate {
   result?: {
     payment_hash?: string;
+    payment_preimage?: string;
     value_sat?: string;
     status: PaymentLifecycleStatus;
     fee_sat?: string;
@@ -48,6 +49,7 @@ export interface AssetPaymentUpdate {
   result?: {
     payment_result?: {
       payment_hash?: string;
+      payment_preimage?: string;
       value_sat?: string;
       status: string;
       fee_sat?: string;
@@ -64,6 +66,8 @@ export interface AssetPaymentUpdate {
 export interface NodePaymentResult {
   status: 'SUCCEEDED' | 'FAILED';
   paymentHash?: string;
+  /** Payment preimage (proof of payment). Present on SUCCEEDED payments. */
+  paymentPreimage?: string;
   feeSat?: string;
   failureReason?: string;
 }