add headless entry point

Summary:
Adding `headless/index.js` This is the entry point to the headless version of Flipper.

This creates a redux store, and initializes the dispatchers. As all business logic (adb connections, etc.) are managed by dispatchers, this spins up a working version of Flipper, listening on our ports, allowing connections to devices.

For APIs not available in node.js, we are adding polyfills. `WebSocket` is used by redux-devtools, `fetch` is used in a couple of places throughout the application. These polyfills are added to the global namespace, so the app can run the same as in the browser.

Reviewed By: passy

Differential Revision: D13786573

fbshipit-source-id: 685f67e1c0d2948de7c43b8a1e2dc10dc69aa743

headless/index.js

@@ -0,0 +1,29 @@
+/**
+ * Copyright 2018-present Facebook.
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * @format
+ */
+
+import {createStore} from 'redux';
+import reducers from '../src/reducers/index.js';
+import dispatcher from '../src/dispatcher/index.js';
+import Logger, {init} from '../src/fb-stubs/Logger.js';
+// $FlowFixMe this file exist, trust me, flow!
+import setup from '../static/setup.js';
+
+// Polyfills
+global.WebSocket = require('ws'); // used for redux devtools
+global.fetch = require('node-fetch/lib/index');
+
+// needs to be required after WebSocket polyfill is loaded
+const devToolsEnhancer = require('remote-redux-devtools').default;
+
+setup();
+const store = createStore(
+  reducers,
+  devToolsEnhancer({realtime: true, hostname: 'localhost', port: 8181}),
+);
+const logger = new Logger(store);
+init(store);
+dispatcher(store, logger);