fix(server): onError should return GraphQLFormattedError (#599)

Co-authored-by: Denis Badurina <[email protected]>
Co-authored-by: enisdenjo <[email protected]>

.changeset/long-glasses-drive.md

@@ -0,0 +1,5 @@
+---
+'graphql-ws': major
+---
+
+`ErrorMessage` uses and `onError` returns `GraphQLFormattedError` (instead of `GraphQLError`)

src/common.ts

@@ -4,8 +4,8 @@
  *
  */
 
-import { GraphQLError } from 'graphql';
-import { areGraphQLErrors, extendedTypeof, isObject } from './utils';
+import { GraphQLError, GraphQLFormattedError } from 'graphql';
+import { areGraphQLFormattedErrors, extendedTypeof, isObject } from './utils';
 
 /**
  * The WebSocket sub-protocol used for the [GraphQL over WebSocket Protocol](https://github.com/graphql/graphql-over-http/blob/main/rfcs/GraphQLOverWebSocket.md).
@@ -169,7 +169,7 @@ export interface NextMessage {
 export interface ErrorMessage {
   readonly id: ID;
   readonly type: MessageType.Error;
-  readonly payload: readonly GraphQLError[];
+  readonly payload: readonly GraphQLFormattedError[];
 }
 
 /** @category Common */
@@ -354,7 +354,7 @@ export function validateMessage(val: unknown): Message {
         );
       }
 
-      if (!areGraphQLErrors(val.payload)) {
+      if (!areGraphQLFormattedErrors(val.payload)) {
         throw new Error(
           `"${
             val.type

src/server.ts

@@ -9,6 +9,7 @@ import {
   getOperationAST,
   GraphQLError,
   execute as graphqlExecute,
+  GraphQLFormattedError,
   GraphQLSchema,
   subscribe as graphqlSubscribe,
   validate as graphqlValidate,
@@ -360,8 +361,8 @@ export interface ServerOptions<
         message: ErrorMessage,
         errors: readonly GraphQLError[],
       ) =>
-        | Promise<readonly GraphQLError[] | void>
-        | readonly GraphQLError[]
+        | Promise<readonly GraphQLFormattedError[] | void>
+        | readonly GraphQLFormattedError[]
         | void);
   /**
    * Executed after an operation has emitted a result right before
@@ -718,7 +719,7 @@ export function makeServer<
                 let errorMessage: ErrorMessage = {
                   id,
                   type: MessageType.Error,
-                  payload: errors,
+                  payload: errors.map((e) => e.toJSON()),
                 };
                 const maybeErrors = await onError?.(ctx, errorMessage, errors);
                 if (maybeErrors)

src/utils.ts

@@ -3,7 +3,7 @@
  * utils
  *
  */
-import { GraphQLError } from 'graphql';
+import { GraphQLError, GraphQLFormattedError } from 'graphql';
 
 /** @private */
 export function extendedTypeof(
@@ -55,7 +55,9 @@ export function isAsyncGenerator<T = unknown>(
 }
 
 /** @private */
-export function areGraphQLErrors(obj: unknown): obj is readonly GraphQLError[] {
+export function areGraphQLFormattedErrors(
+  obj: unknown,
+): obj is readonly GraphQLFormattedError[] {
   return (
     Array.isArray(obj) &&
     // must be at least one error
@@ -65,6 +67,17 @@ export function areGraphQLErrors(obj: unknown): obj is readonly GraphQLError[] {
   );
 }
 
+/** @private */
+export function areGraphQLErrors(obj: unknown): obj is readonly GraphQLError[] {
+  return (
+    Array.isArray(obj) &&
+    // must be at least one error
+    obj.length > 0 &&
+    // error has at least a message
+    obj.every((ob) => ob instanceof GraphQLError)
+  );
+}
+
 /**
  * Limits the WebSocket close event reason to not exceed a length of one frame.
  * Reference: https://datatracker.ietf.org/doc/html/rfc6455#section-5.2.

tests/server.test.ts

@@ -1077,7 +1077,10 @@ describe.concurrent('Subscribe', () => {
   }) => {
     const { url } = await startTServer({
       onError: (_ctx, _message) => {
-        return [new GraphQLError('Itsa me!'), new GraphQLError('Anda me!')];
+        return [
+          new GraphQLError('Itsa me!').toJSON(),
+          new GraphQLError('Anda me!').toJSON(),
+        ];
       },
     });