Simplify subscription example

Motivation: use one example to run query/mutation/subscription
Also don't use unnessary 3rd-party packages in examples

README.md

@@ -74,16 +74,8 @@ app.listen(4000);
 const express = require('express');
 const { graphqlHTTP } = require('express-graphql');
 
-const typeDefs = require('./schema');
-const resolvers = require('./resolvers');
-const { makeExecutableSchema } = require('graphql-tools');
-const schema = makeExecutableSchema({
-  typeDefs: typeDefs,
-  resolvers: resolvers,
-});
-
-const { execute, subscribe } = require('graphql');
 const { createServer } = require('http');
+const { execute, subscribe } = require('graphql');
 const { SubscriptionServer } = require('subscriptions-transport-ws');
 
 const PORT = 4000;
@@ -93,7 +85,7 @@ var app = express();
 app.use(
   '/graphql',
   graphqlHTTP({
-    schema: schema,
+    schema: MyGraphQLSchema,
     graphiql: { subscriptionEndpoint: `ws://localhost:${PORT}/subscriptions` },
   }),
 );
@@ -102,7 +94,7 @@ const ws = createServer(app);
 
 ws.listen(PORT, () => {
   // Set up the WebSocket for handling GraphQL subscriptions.
-  new SubscriptionServer(
+  SubscriptionServer.create(
     {
       execute,
       subscribe,
@@ -142,9 +134,9 @@ The `graphqlHTTP` function accepts the following options:
   - **`headers`**: An optional string of initial state for the header editor. Only makes sense if headerEditorEnabled is `true`.
     Defaults to empty.
 
-  - **`subscriptionEndpoint`**: An optional GraphQL string contains the WebSocket server url for subscription.
+  - **`subscriptionEndpoint`**: An optional string contains the WebSocket server url for subscription.
 
-  - **`websocketClient`**: An optional GraphQL string for websocket client used for subscription, `v0`: subscriptions-transport-ws, `v1`: graphql-ws. Defaults to `v0` if not provided
+  - **`websocketClient`**: An optional string for websocket client used for subscription, `v0`: subscriptions-transport-ws, `v1`: graphql-ws. Defaults to `v0` if not provided
 
 - **`rootValue`**: A value to pass as the `rootValue` to the `execute()`
   function from [`GraphQL.js/src/execute.ts`](https://github.com/graphql/graphql-js/blob/main/src/execution/execute.ts#L148).

examples/index.ts

@@ -1,28 +1,72 @@
+import { createServer } from 'http';
+
 import express from 'express';
-import { buildSchema } from 'graphql';
+import { execute, subscribe, buildSchema } from 'graphql';
+import { SubscriptionServer } from 'subscriptions-transport-ws';
 
 import { graphqlHTTP } from '../src';
 
 // Construct a schema, using GraphQL schema language
 const schema = buildSchema(`
   type Query {
-    hello: String
+    hello: String!
+  }
+
+  type Subscription {
+    currentTime: String!
   }
 `);
 
 // The root provides a resolver function for each API endpoint
 const rootValue = {
   hello: () => 'Hello world!',
+  currentTime: () => currentTimeGenerator(),
 };
 
+async function* currentTimeGenerator() {
+  while (true) {
+    const currentTime = (new Date()).toLocaleTimeString();
+    console.log('Pushed current time over subscriptions: ' + currentTime);
+    yield { currentTime };
+
+    await later(1);
+  }
+}
+
+function later(delayInSeconds: number) {
+  return new Promise((resolve) => setTimeout(resolve, delayInSeconds * 1000));
+}
+
+const PORT = 4001;
 const app = express();
 app.use(
   '/graphql',
   graphqlHTTP({
     schema,
     rootValue,
-    graphiql: { headerEditorEnabled: true },
+    graphiql: {
+      headerEditorEnabled: true,
+      subscriptionEndpoint: `ws://localhost:${PORT}/subscriptions`,
+    },
   }),
 );
-app.listen(4000);
-console.log('Running a GraphQL API server at http://localhost:4000/graphql');
+
+const ws = createServer(app);
+
+ws.listen(PORT, () => {
+  // Set up the WebSocket for handling GraphQL subscriptions.
+  SubscriptionServer.create(
+    {
+      execute,
+      subscribe,
+      schema,
+      rootValue,
+    },
+    {
+      server: ws,
+      path: '/subscriptions',
+    },
+  );
+});
+
+console.log(`Running a GraphQL API server at http://localhost:${PORT}/graphql`);

package.json

@@ -48,9 +48,7 @@
     "check:spelling": "cspell '**/*'",
     "check:integrations": "mocha --full-trace integrationTests/*-test.js",
     "build:npm": "node resources/build-npm.js",
-    "start": "node -r ./resources/register.js examples/index.ts",
-    "start:subscription": "node -r ./resources/register.js examples/index_subscription.ts",
-    "start:subscription_legacy": "node -r ./resources/register.js examples/index_subscription_legacy.ts"
+    "start": "node -r ./resources/register.js examples/index.ts"
   },
   "dependencies": {
     "accepts": "^1.3.7",
@@ -100,7 +98,6 @@
     "react-dom": "16.14.0",
     "restify": "8.5.1",
     "sinon": "9.2.1",
-    "subscriptions-transport-ws": "0.9.18",
     "supertest": "6.0.1",
     "ts-node": "9.0.0",
     "typescript": "4.1.2",