From 33e64db9e8730f0c716fcdd41c93014d48f1796a Mon Sep 17 00:00:00 2001
From: tpoisseau <22891227+tpoisseau@users.noreply.github.com>
Date: Fri, 8 Nov 2024 11:26:16 +0100
Subject: [PATCH] fix: properly type `extensions` in GraphQLFormattedError
 (#4286)

Following typescript documentation, it's not possible override interface
property, we can only add new props.

Since it's declared as unknown dict, even if we merge
`GraphQLErrorExtensions`, we can't access to our extensions without
workaround and verbose typescript in source-code.

It's annoying since apollo expose `GraphQLFormattedError` instead
`GraphQLError`

Refs:
https://www.typescriptlang.org/docs/handbook/declaration-merging.html
Refs: https://github.com/apollographql/apollo-client/pull/11789
---
 src/error/GraphQLError.ts | 15 ++++++++++++++-
 src/error/index.ts        |  1 +
 src/index.ts              |  1 +
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/error/GraphQLError.ts b/src/error/GraphQLError.ts
index a3ce229968..a2404d6040 100644
--- a/src/error/GraphQLError.ts
+++ b/src/error/GraphQLError.ts
@@ -23,6 +23,19 @@ export interface GraphQLErrorExtensions {
   [attributeName: string]: unknown;
 }
 
+/**
+ * Custom formatted extensions
+ *
+ * @remarks
+ * Use a unique identifier name for your extension, for example the name of
+ * your library or project. Do not use a shortened identifier as this increases
+ * the risk of conflicts. We recommend you add at most one extension field,
+ * an object which can contain all the values you need.
+ */
+export interface GraphQLFormattedErrorExtensions {
+  [attributeName: string]: unknown;
+}
+
 export interface GraphQLErrorOptions {
   nodes?: ReadonlyArray<ASTNode> | ASTNode | null | undefined;
   source?: Maybe<Source>;
@@ -238,5 +251,5 @@ export interface GraphQLFormattedError {
    * Reserved for implementors to extend the protocol however they see fit,
    * and hence there are no additional restrictions on its contents.
    */
-  readonly extensions?: { [key: string]: unknown };
+  readonly extensions?: GraphQLFormattedErrorExtensions;
 }
diff --git a/src/error/index.ts b/src/error/index.ts
index ed9e24d241..17e9059dd1 100644
--- a/src/error/index.ts
+++ b/src/error/index.ts
@@ -3,6 +3,7 @@ export type {
   GraphQLErrorOptions,
   GraphQLFormattedError,
   GraphQLErrorExtensions,
+  GraphQLFormattedErrorExtensions,
 } from './GraphQLError.js';
 
 export { syntaxError } from './syntaxError.js';
diff --git a/src/index.ts b/src/index.ts
index c3deb51ffe..fe3b2b1a80 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -423,6 +423,7 @@ export type {
   GraphQLErrorOptions,
   GraphQLFormattedError,
   GraphQLErrorExtensions,
+  GraphQLFormattedErrorExtensions,
 } from './error/index.js';
 
 // Utilities for operating on GraphQL type schema and parsed sources.