fix: do not throw error if resolver is a built-in one

Author: gregberge

Diff for: src/addDirectiveResolveFunctionsToSchema.js

@@ -3,6 +3,8 @@ import { defaultFieldResolver } from 'graphql'
 import { DirectiveLocation } from 'graphql/type'
 import { getArgumentValues } from 'graphql/execution/values'
 
+const BUILT_IN_DIRECTIVES = ['deprecated', 'skip', 'include']
+
 function getFieldResolver(field) {
   const resolver = field.resolve || defaultFieldResolver
   return resolver.bind(field)
@@ -33,7 +35,7 @@ function getDirectiveInfo(directive, resolverMap, schema, location) {
   }
 
   const resolver = resolverMap[name]
-  if (!resolver) {
+  if (!resolver && !BUILT_IN_DIRECTIVES.includes(name)) {
     throw new Error(
       `Directive @${name} has no resolver.` +
         'Please define one using createFieldExecutionResolver().',

Diff for: src/addDirectiveResolveFunctionsToSchema.test.js

@@ -175,6 +175,21 @@ describe('addDirectiveResolveFunctionsToSchema', () => {
       }
     })
 
+    it('should not throw an error if resolver is a built-in one', async () => {
+      const typeDefs = /* GraphQL */ `
+        type Query {
+          foo: String @deprecated
+        }
+      `
+      const resolvers = {
+        Query: {
+          foo: () => 'foo',
+        },
+      }
+      const schema = makeExecutableSchema({ typeDefs, resolvers })
+      addDirectiveResolveFunctionsToSchema(schema, {})
+    })
+
     it('should work without directive', async () => {
       const query = /* GraphQL */ `{ foo }`
       const data = await run(schema, query)