extendSchema: inline ASTDefinitionBuilder class methods

Author: IvanGoncharov

src/type/schema.d.ts

@@ -112,3 +112,14 @@ export interface GraphQLSchemaConfig extends GraphQLSchemaValidationOptions {
   astNode?: Maybe<SchemaDefinitionNode>;
   extensionASTNodes?: Maybe<ReadonlyArray<SchemaExtensionNode>>;
 }
+
+/**
+ * @internal
+ */
+export interface GraphQLSchemaNormalizedConfig extends GraphQLSchemaConfig {
+  types: Array<GraphQLNamedType>;
+  directives: Array<GraphQLDirective>;
+  extensions: Maybe<Readonly<Record<string, any>>>;
+  extensionASTNodes: Maybe<ReadonlyArray<SchemaExtensionNode>>;
+  assumeValid: boolean;
+}

src/utilities/extendSchema.d.ts

@@ -1,6 +1,10 @@
 import Maybe from '../tsutils/Maybe';
 import { Location, DocumentNode, StringValueNode } from '../language/ast';
-import { GraphQLSchemaValidationOptions, GraphQLSchema } from '../type/schema';
+import {
+  GraphQLSchemaValidationOptions,
+  GraphQLSchema,
+  GraphQLSchemaNormalizedConfig,
+} from '../type/schema';
 
 interface Options extends GraphQLSchemaValidationOptions {
   /**
@@ -45,6 +49,15 @@ export function extendSchema(
   options?: Options,
 ): GraphQLSchema;
 
+/**
+ * @internal
+ */
+export function extendSchemaImpl(
+  schemaConfig: GraphQLSchemaNormalizedConfig,
+  documentAST: DocumentNode,
+  options?: Options,
+): GraphQLSchemaNormalizedConfig;
+
 /**
  * Given an ast node, returns its string description.
  * @deprecated: provided to ease adoption and will be removed in v16.