update js-client api (migrate to TS)

Summary:
JS/TS api:
- migrate to TS
- some refactoring (get rid of bridge, make client abstract)

Implementation isn't full yet, things to be implemented:
- let plugins connect on init command from Flipper
- implement Responder

Further plans:
- make fully compatible with react-native api without breaking changes

Reviewed By: mweststrate

Differential Revision: D21839377

fbshipit-source-id: 9e9fe4ad01632f958b59eb255c703c6cbc5fafe2

flipper-js-client-sdk/src/webviewImpl.ts

@@ -0,0 +1,58 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import {FlipperClient} from './api';
+
+import type {FlipperPluginID, FlipperMethodID} from './api';
+
+class FlipperWebviewClient extends FlipperClient {
+  _subscriptions: Map<string, (message: any) => void> = new Map();
+  _client: FlipperClient | null = null;
+
+  start = (appName: string) => {
+    const bridge = (window as any).FlipperWebviewBridge;
+    bridge?.registerPlugins(this.plugins);
+    bridge?.start(appName);
+  };
+
+  stop = () => {
+    const bridge = (window as any).FlipperWebviewBridge;
+    bridge?.FlipperWebviewBridge.stop();
+  };
+
+  sendData = (plugin: FlipperPluginID, method: FlipperMethodID, data: any) => {
+    const bridge = (window as any).FlipperWebviewBridge;
+    bridge && bridge.sendFlipperObject(plugin, method, JSON.stringify(data));
+  };
+
+  subscribe = (
+    plugin: FlipperPluginID,
+    method: FlipperMethodID,
+    handler: (msg: any) => void,
+  ) => {
+    this._subscriptions.set(plugin + method, handler);
+  };
+
+  isAvailable = () => {
+    return (window as any).FlipperWebviewBridge != null;
+  };
+
+  receive(plugin: FlipperPluginID, method: FlipperMethodID, data: string) {
+    const handler = this._subscriptions.get(plugin + method);
+    handler && handler(JSON.parse(data));
+  }
+
+  setClient(client: FlipperClient) {
+    this._client = client;
+  }
+}
+
+export function newWebviewClient(): FlipperClient {
+  return new FlipperWebviewClient();
+}