Export "SubscriptionArgs" type (#1942)

src/index.js

@@ -295,6 +295,7 @@ export {
 export type { ExecutionArgs, ExecutionResult } from './execution';
 
 export { subscribe, createSourceEventStream } from './subscription';
+export type { SubscriptionArgs } from './subscription';
 
 // Validate GraphQL documents.
 export {

src/subscription/index.js

@@ -8,3 +8,4 @@
  */
 
 export { subscribe, createSourceEventStream } from './subscribe';
+export type { SubscriptionArgs } from './subscribe';

src/subscription/subscribe.js

@@ -30,6 +30,17 @@ import { type DocumentNode } from '../language/ast';
 import { type GraphQLFieldResolver } from '../type/definition';
 import { getOperationRootType } from '../utilities/getOperationRootType';
 
+export type SubscriptionArgs = {|
+  schema: GraphQLSchema,
+  document: DocumentNode,
+  rootValue?: mixed,
+  contextValue?: mixed,
+  variableValues?: ?{ [variable: string]: mixed },
+  operationName?: ?string,
+  fieldResolver?: ?GraphQLFieldResolver<any, any>,
+  subscribeFieldResolver?: ?GraphQLFieldResolver<any, any>,
+|};
+
 /**
  * Implements the "Subscribe" algorithm described in the GraphQL specification.
  *
@@ -51,16 +62,7 @@ import { getOperationRootType } from '../utilities/getOperationRootType';
  * Accepts either an object with named arguments, or individual arguments.
  */
 declare function subscribe(
-  {|
-    schema: GraphQLSchema,
-    document: DocumentNode,
-    rootValue?: mixed,
-    contextValue?: mixed,
-    variableValues?: ?{ [variable: string]: mixed },
-    operationName?: ?string,
-    fieldResolver?: ?GraphQLFieldResolver<any, any>,
-    subscribeFieldResolver?: ?GraphQLFieldResolver<any, any>,
-  |},
+  SubscriptionArgs,
   ..._: []
 ): Promise<AsyncIterator<ExecutionResult> | ExecutionResult>;
 /* eslint-disable no-redeclare */