POC for graphql#3362 (comment)

Author: spawnia

src/type/directives.ts

@@ -9,8 +9,8 @@ import type { DirectiveDefinitionNode } from '../language/ast';
 import { DirectiveLocation } from '../language/directiveLocation';
 
 import type {
-  GraphQLArgument,
-  GraphQLFieldConfigArgumentMap,
+  GraphQLArgument, GraphQLEnumValue, GraphQLField,
+  GraphQLFieldConfigArgumentMap, GraphQLInputField, GraphQLType,
 } from './definition';
 import { assertName } from './assertName';
 import { GraphQLString, GraphQLBoolean } from './scalars';
@@ -109,6 +109,8 @@ export class GraphQLDirective {
   }
 }
 
+type DirectiveExposeArgs = (definition: GraphQLType|GraphQLField<unknown, unknown>|GraphQLEnumValue|GraphQLInputField|GraphQLArgument) => Record<string, string>
+
 export interface GraphQLDirectiveConfig {
   name: string;
   description?: Maybe<string>;
@@ -117,6 +119,7 @@ export interface GraphQLDirectiveConfig {
   isRepeatable?: Maybe<boolean>;
   extensions?: Maybe<Readonly<GraphQLDirectiveExtensions>>;
   astNode?: Maybe<DirectiveDefinitionNode>;
+  exposeArgs?: Maybe<DirectiveExposeArgs>
 }
 
 interface GraphQLDirectiveNormalizedConfig extends GraphQLDirectiveConfig {
@@ -191,6 +194,15 @@ export const GraphQLDeprecatedDirective: GraphQLDirective =
         defaultValue: DEFAULT_DEPRECATION_REASON,
       },
     },
+    exposeArgs: (definition: GraphQLField<unknown, unknown>|GraphQLInputField|GraphQLEnumValue) => {
+      if (definition.deprecationReason != null) {
+        return [
+          definition.deprecationReason === DEFAULT_DEPRECATION_REASON
+              ? {}
+              : { reason: definition.deprecationReason },
+        ];
+      }
+    }
   });
 
 /**