feat(execution): add field batch resolver mode

Introduce the experimental field batch resolver execution mode behind enableBatchResolvers: 'field'. The option is typed by BatchResolverLevel, and regular field execution remains the path for fields that do not define experimentalBatchResolve.

Example option:

  execute({ schema, document, enableBatchResolvers: 'field' });

Example field resolver:

  const name = {

    type: GraphQLString,

    experimentalBatchResolve: (sources) =>

      sources.map((source) => source.name),

  };

Author: yaacovCR

benchmark/batch-resolution-benchmark.js

@@ -14,6 +14,10 @@ const WidgetType = new GraphQLObjectType({
     id: { type: GraphQLID },
     widget: {
       type: WidgetType,
+      resolve: async (source) => {
+        await Promise.resolve();
+        return source.widget;
+      },
       experimentalBatchResolve: async (sources) => {
         await Promise.resolve();
         return sources.map((source) => source.widget);
@@ -45,11 +49,12 @@ const rootValue = {
 const document = parse(`{ widgets(first: 10000) { id widget { id } } }`);
 
 export const benchmark = {
-  name: 'Execute Batch Resolved Widget Field',
+  name: 'Execute Async Widget Field With Batch Resolver',
   measure: () =>
     execute({
       schema,
       document,
       rootValue,
+      enableBatchResolvers: true,
     }),
 };