Fix: make public API compatible with 'exactOptionalPropertyTypes'

It's recomended option that was added in TS 4.4 but our public API
was not compatible with it. Meaning if project was using graphql-js
and had this enabled this flag they lost ability to explicitly pass
undefined values.

Author: IvanGoncharov

integrationTests/ts/kitchenSink-test.ts

@@ -0,0 +1,16 @@
+import { GraphQLScalarType } from 'graphql/type';
+import { GraphQLError } from 'graphql/error';
+import type { NameNode } from 'graphql/language';
+import { Kind } from 'graphql/language';
+
+// Test subset of public APIs with "exactOptionalPropertyTypes" flag enabled
+new GraphQLScalarType({
+  name: 'SomeScalar',
+  serialize: undefined,
+  parseValue: undefined,
+  parseLiteral: undefined,
+});
+
+new GraphQLError('test', { nodes: undefined });
+
+const nameNode: NameNode = { kind: Kind.NAME, loc: undefined, value: 'test' };

integrationTests/ts/tsconfig.json

@@ -2,8 +2,9 @@
   "compilerOptions": {
     "module": "commonjs",
     "lib": ["es2019", "es2020.promise", "es2020.bigint", "es2020.string"],
-    "strict": true,
     "noEmit": true,
-    "types": []
+    "types": [],
+    "strict": true,
+    "exactOptionalPropertyTypes": true
   }
 }

src/error/GraphQLError.ts

@@ -21,7 +21,7 @@ export interface GraphQLErrorExtensions {
 }
 
 export interface GraphQLErrorOptions {
-  nodes?: ReadonlyArray<ASTNode> | ASTNode | null;
+  nodes?: ReadonlyArray<ASTNode> | ASTNode | null | undefined;
   source?: Maybe<Source>;
   positions?: Maybe<ReadonlyArray<number>>;
   path?: Maybe<ReadonlyArray<string | number>>;

src/execution/__tests__/union-interface-test.ts

@@ -44,8 +44,8 @@ class Cat {
 
 class Person {
   name: string;
-  pets?: ReadonlyArray<Dog | Cat>;
-  friends?: ReadonlyArray<Dog | Cat | Person>;
+  pets: ReadonlyArray<Dog | Cat> | undefined;
+  friends: ReadonlyArray<Dog | Cat | Person> | undefined;
 
   constructor(
     name: string,

src/execution/values.ts

@@ -238,7 +238,7 @@ export function getArgumentValues(
  */
 export function getDirectiveValues(
   directiveDef: GraphQLDirective,
-  node: { readonly directives?: ReadonlyArray<DirectiveNode> },
+  node: { readonly directives?: ReadonlyArray<DirectiveNode> | undefined },
   variableValues?: Maybe<ObjMap<unknown>>,
 ): undefined | { [argument: string]: unknown } {
   const directiveNode = node.directives?.find(