Add isMethodSupported to client

Summary: Allows plugins to check if extension commands or new features are enabled in the current app, by calling `this.client.supportsMethod('xxx')`.

Reviewed By: passy

Differential Revision: D14225961

fbshipit-source-id: c9f7f5b3091209f0ce9705d9d3a0ec173edf3e25

src/Client.js

@@ -469,4 +469,13 @@ export default class Client extends EventEmitter {
     }
     return this.rawSend('execute', {api, method, params});
   }
+
+  supportsMethod(api: string, method: string): Promise<boolean> {
+    if (this.sdkVersion < 2) {
+      return Promise.resolve(false);
+    }
+    return this.rawCall('isMethodSupported', {api, method}).then(
+      response => response.isSupported,
+    );
+  }
 }

src/plugin.js

@@ -23,6 +23,7 @@ export type PluginClient = {|
   send: (method: string, params?: Object) => void,
   call: (method: string, params?: Object) => Promise<any>,
   subscribe: (method: string, callback: (params: any) => void) => void,
+  supportsMethod: (method: string) => Promise<boolean>,
 |};
 
 type PluginTarget = BaseDevice | Client;
@@ -168,6 +169,7 @@ export class FlipperPlugin<S = *, A = *, P = *> extends FlipperBasePlugin<
         });
         this.realClient.subscribe(id, method, callback);
       },
+      supportsMethod: method => this.realClient.supportsMethod(id, method),
     };
   }