Add FlipperServerClient to headless tic-tac-toe

Summary: FlipperServerClient is a high-level abstraction to talk to Flipper Server

Reviewed By: passy

Differential Revision: D36545544

fbshipit-source-id: 12845a96dfc39d4268d2f7134d90d5addae48b83

desktop/examples/headless-tic-tac-toe/flipperClient.js

@@ -0,0 +1,77 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+const WebSocket = require('ws');
+const EventEmitter = require('events');
+
+class FlipperServerClient {
+  messageId = 0;
+  wsClient = new WebSocket('ws://localhost:52342?server_companion=true');
+  execReqs = new Map();
+  eventBus = new EventEmitter();
+
+  async init() {
+    await new Promise((resolve) => this.wsClient.on('open', resolve));
+
+    this.wsClient.on('message', (data) => {
+      const {event, payload} = JSON.parse(data);
+
+      switch (event) {
+        case 'exec-response':
+        case 'exec-response-error': {
+          const req = this.execReqs.get(payload.id);
+
+          if (!req) {
+            console.warn('Unknown exec request');
+            return;
+          }
+
+          this.execReqs.delete(payload.id);
+
+          if (event === 'exec-response') {
+            req.resolve(payload.data);
+          } else {
+            req.reject(payload.data);
+          }
+          return;
+        }
+        case 'companion-event': {
+          this.eventBus.emit(payload.event, payload.data);
+        }
+      }
+    });
+  }
+
+  exec(command, args) {
+    return new Promise((resolve, reject) => {
+      const id = this.messageId++;
+
+      this.wsClient.send(
+        JSON.stringify({
+          event: 'exec',
+          payload: {
+            id,
+            command,
+            args,
+          },
+        }),
+      );
+
+      this.execReqs.set(id, {resolve, reject});
+    });
+  }
+
+  on(eventName, cb) {
+    this.eventBus.on(eventName, cb);
+  }
+}
+
+module.exports = {
+  FlipperServerClient,
+};