feat(handler): Custom GraphQL getOperationAST option

Author: enisdenjo

docs/interfaces/HandlerOptions.md

@@ -14,6 +14,7 @@
 
 - [context](HandlerOptions.md#context)
 - [execute](HandlerOptions.md#execute)
+- [getOperationAST](HandlerOptions.md#getoperationast)
 - [onOperation](HandlerOptions.md#onoperation)
 - [onSubscribe](HandlerOptions.md#onsubscribe)
 - [parse](HandlerOptions.md#parse)
@@ -61,6 +62,31 @@ a GraphQLError will be thrown immediately explaining the invalid input.
 
 ___
 
+### getOperationAST
+
+• `Optional` **getOperationAST**: (`documentAST`: `DocumentNode`, `operationName?`: `Maybe`<`string`\>) => `Maybe`<`OperationDefinitionNode`\>
+
+#### Type declaration
+
+▸ (`documentAST`, `operationName?`): `Maybe`<`OperationDefinitionNode`\>
+
+Returns an operation AST given a document AST and optionally an operation
+name. If a name is not provided, an operation is only returned if only one is
+provided in the document.
+
+##### Parameters
+
+| Name | Type |
+| :------ | :------ |
+| `documentAST` | `DocumentNode` |
+| `operationName?` | `Maybe`<`string`\> |
+
+##### Returns
+
+`Maybe`<`OperationDefinitionNode`\>
+
+___
+
 ### onOperation
 
 • `Optional` **onOperation**: (`req`: [`Request`](Request.md)<`RawRequest`\>, `args`: `ExecutionArgs`, `result`: `ExecutionResult`<`ObjMap`<`unknown`\>, `ObjMap`<`unknown`\>\>) => `void` \| [`Response`](../README.md#response) \| `ExecutionResult`<`ObjMap`<`unknown`\>, `ObjMap`<`unknown`\>\> \| `Promise`<`void` \| [`Response`](../README.md#response) \| `ExecutionResult`<`ObjMap`<`unknown`\>, `ObjMap`<`unknown`\>\>\>

src/handler.ts

@@ -12,7 +12,7 @@ import {
   execute as graphqlExecute,
   parse as graphqlParse,
   DocumentNode,
-  getOperationAST,
+  getOperationAST as graphqlGetOperationAST,
   OperationTypeNode,
 } from 'graphql';
 import { isResponse, Request, RequestParams, Response } from './common';
@@ -86,6 +86,10 @@ export interface HandlerOptions<RawRequest = unknown> {
    * GraphQL parse function allowing you to apply a custom parser.
    */
   parse?: typeof graphqlParse;
+  /**
+   * GraphQL operation AST getter used for detecting the operation type.
+   */
+  getOperationAST?: typeof graphqlGetOperationAST;
   /**
    * The subscribe callback executed right after processing the request
    * before proceeding with the GraphQL operation execution.
@@ -215,6 +219,7 @@ export function createHandler<RawRequest = unknown>(
     validate = graphqlValidate,
     execute = graphqlExecute,
     parse = graphqlParse,
+    getOperationAST = graphqlGetOperationAST,
     onSubscribe,
     onOperation,
   } = options;