Dev/grpc mobile error message

mobile/ios/lightning/LndReactModule.m

@@ -38,7 +38,7 @@ - (instancetype)initWithResolver: (RCTPromiseResolveBlock)resolve rejecter:(RCTP
 }
 
 - (void)onError:(NSError *)p0 {
-    self.reject(@"error", @"received error", p0);
+    self.reject(@"error", [p0 localizedDescription], p0);
 }
 
 - (void)onResponse:(NSData *)p0 {

src/action/grpc-mobile.js

@@ -165,10 +165,18 @@ class GrpcAction {
   //
 
   async _lnrpcRequest(method, body) {
-    method = toCaps(method);
-    const req = this._serializeRequest(method, body);
-    const response = await this._lnd.sendCommand(method, req);
-    return this._deserializeResponse(method, response.data);
+    try {
+      method = toCaps(method);
+      const req = this._serializeRequest(method, body);
+      const response = await this._lnd.sendCommand(method, req);
+      return this._deserializeResponse(method, response.data);
+    } catch (err) {
+      if (typeof err === 'string') {
+        throw new Error(err);
+      } else {
+        throw err;
+      }
+    }
   }
 
   _serializeRequest(method, body = {}) {

src/action/payment.js

@@ -247,7 +247,7 @@ class PaymentAction {
       this._nav.goPayBitcoinConfirm();
     } catch (err) {
       this._notification.display({
-        msg: `Fee estimation failed: ${err.details}`,
+        msg: `Fee estimation failed: ${err.message}`,
         err,
       });
     }

test/unit/action/grpc-mobile.spec.js

@@ -161,6 +161,24 @@ describe('Action GRPC Mobile Unit Tests', () => {
   });
 
   describe('sendCommand()', () => {
+    it('should handle string error mesage', async () => {
+      LndReactModuleStub.sendCommand.returns(Promise.reject('some-message'));
+      await expect(
+        grpc.sendCommand('GetInfo'),
+        'to be rejected with error satisfying',
+        /some-message/
+      );
+    });
+
+    it('should handle error object', async () => {
+      LndReactModuleStub.sendCommand.rejects(new Error('some-message'));
+      await expect(
+        grpc.sendCommand('GetInfo'),
+        'to be rejected with error satisfying',
+        /some-message/
+      );
+    });
+
     it('should work for GetInfo (without body)', async () => {
       LndReactModuleStub.sendCommand.resolves({
         data: grpc._serializeResponse('GetInfo'),