refactor(graphql-server): enable isolated declarations (#1197)

.changeset/huge-clocks-behave.md

@@ -0,0 +1,5 @@
+---
+'@hono/graphql-server': patch
+---
+
+Add explicit `Response` return type

packages/graphql-server/src/index.ts

@@ -216,7 +216,9 @@ export const getGraphQLParams = async (request: Request): Promise<GraphQLParams>
 export const errorMessages = (
   messages: string[],
   graphqlErrors?: readonly GraphQLError[] | readonly GraphQLFormattedError[]
-) => {
+): {
+  errors: readonly GraphQLError[] | readonly GraphQLFormattedError[]
+} => {
   if (graphqlErrors) {
     return {
       errors: graphqlErrors,
@@ -232,7 +234,7 @@ export const errorMessages = (
   }
 }
 
-export const respondWithGraphiQL = (c: Context) => {
+export const respondWithGraphiQL = (c: Context): Response => {
   // https://github.com/graphql/graphiql/blob/03171d5614c61fb345763636d120da2b536d54a0/examples/graphiql-cdn/index.html
   return c.html(`<!--
  *  Copyright (c) 2021 GraphQL Contributors

packages/graphql-server/tsconfig.build.json

@@ -4,7 +4,8 @@
     "rootDir": "src",
     "outDir": "dist",
     "tsBuildInfoFile": "dist/tsconfig.build.tsbuildinfo",
-    "emitDeclarationOnly": false
+    "emitDeclarationOnly": false,
+    "isolatedDeclarations": true
   },
   "include": ["src/**/*.ts"],
   "exclude": ["**/*.test.ts"],