Add missing parameter types

src/__tests__/http-test.js

@@ -19,6 +19,7 @@ import {
   GraphQLNonNull,
   GraphQLString,
   GraphQLError,
+  ValidationContext,
   BREAK,
   Source,
   validate,
@@ -1962,7 +1963,9 @@ function runTests(server) {
   });
 
   describe('Custom validation rules', () => {
-    const AlwaysInvalidRule = function (context) {
+    const AlwaysInvalidRule = function (
+      context: ValidationContext,
+    ): { [key: string]: mixed, ... } {
       return {
         enter() {
           context.reportError(

src/index.js

@@ -194,7 +194,7 @@ export function graphqlHTTP(options: Options): Middleware {
   return async function graphqlMiddleware(
     request: $Request,
     response: $Response,
-  ) {
+  ): Promise<void> {
     // Higher scoped variables are referred to at various stages in the asynchronous state machine below.
     let params: GraphQLParams;
     let showGraphiQL = false;

src/parseBody.js

@@ -1,7 +1,7 @@
 // @flow strict
 
 import { type IncomingMessage } from 'http';
-import zlib from 'zlib';
+import zlib, { type Inflate, type Gunzip } from 'zlib';
 import querystring from 'querystring';
 
 import getBody from 'raw-body';
@@ -76,7 +76,11 @@ export async function parseBody(
 const jsonObjRegex = /^[ \t\n\r]*\{/;
 
 // Read and parse a request body.
-async function readBody(req, typeInfo) {
+async function readBody(
+  req: $Request,
+  // TODO: Import the appropriate TS type and use it here instead
+  typeInfo: {| type: string, parameters: { [param: string]: string, ... } |},
+): Promise<string> {
   const charset = (typeInfo.parameters.charset ?? 'utf-8').toLowerCase();
 
   // Assert charset encoding per JSON RFC 7159 sec 8.1
@@ -105,7 +109,10 @@ async function readBody(req, typeInfo) {
 }
 
 // Return a decompressed stream, given an encoding.
-function decompressed(req, encoding) {
+function decompressed(
+  req: $Request,
+  encoding: string,
+): $Request | Inflate | Gunzip {
   switch (encoding) {
     case 'identity':
       return req;

src/renderGraphiQL.js

@@ -19,9 +19,9 @@ export type GraphiQLOptions = {|
 |};
 
 // Ensures string values are safe to be used within a <script> tag.
-function safeSerialize(data) {
+function safeSerialize(data: mixed): string {
   return data != null
-    ? JSON.stringify(data).replace(/\//g, '\\/')
+    ? ((JSON.stringify(data): any): string).replace(/\//g, '\\/')
     : 'undefined';
 }