Extracting utility methods

Summary:
Extract the following utility functions from ServerController:

transformCertificateExchangeMediumToType
appNameWithUpdateHint

The functions are not tied to the ServerController and will be used outside of it.

Reviewed By: passy

Differential Revision: D29938355

fbshipit-source-id: ea489f54a3a6bf46ae4e108579d48ede1f891093

desktop/app/src/comms/ServerController.tsx

@@ -46,6 +46,10 @@ import DummyDevice from '../devices/DummyDevice';
 import BaseDevice from '../devices/BaseDevice';
 import {sideEffect} from '../utils/sideEffect';
 import {destroyDevice} from '../reducers/connections';
+import {
+  appNameWithUpdateHint,
+  transformCertificateExchangeMediumToType,
+} from './Utilities';
 
 type ClientInfo = {
   connection: ClientConnection | null | undefined;
@@ -57,35 +61,12 @@ type ClientCsrQuery = {
   csr_path?: string | undefined;
 };
 
-function transformCertificateExchangeMediumToType(
-  medium: number | undefined,
-): CertificateExchangeMedium {
-  if (medium == 1) {
-    return 'FS_ACCESS';
-  } else if (medium == 2) {
-    return 'WWW';
-  } else {
-    return 'FS_ACCESS';
-  }
-}
-
 declare interface ServerController {
   on(event: 'new-client', callback: (client: Client) => void): this;
   on(event: 'error', callback: (err: Error) => void): this;
   on(event: 'clients-change', callback: () => void): this;
 }
 
-function appNameWithUpdateHint(query: ClientQuery): string {
-  // in previous version (before 3), app may not appear in correct device
-  // section because it refers to the name given by client which is not fixed
-  // for android emulators, so it is indicated as outdated so that developers
-  // might want to update SDK to get rid of this connection swap problem
-  if (query.os === 'Android' && (!query.sdk_version || query.sdk_version < 3)) {
-    return query.app + ' (Outdated SDK)';
-  }
-  return query.app;
-}
-
 class ServerController extends EventEmitter {
   connections: Map<string, ClientInfo>;
   secureServer: Promise<RSocketServer<any, any>> | null;

desktop/app/src/comms/Utilities.tsx

@@ -0,0 +1,46 @@
+/**
+ * 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 {CertificateExchangeMedium} from '../utils/CertificateProvider';
+import {ClientQuery} from '../Client';
+
+/**
+ * Transforms the certificate exchange medium type as number to the
+ * CertificateExchangeMedium type.
+ * @param medium A number representing the certificate exchange medium type.
+ */
+export function transformCertificateExchangeMediumToType(
+  medium: number | undefined,
+): CertificateExchangeMedium {
+  if (medium == 1) {
+    return 'FS_ACCESS';
+  } else if (medium == 2) {
+    return 'WWW';
+  } else {
+    return 'FS_ACCESS';
+  }
+}
+
+/**
+ * Returns the app name from a ClientQuery instance. In most cases it should be
+ * the app name as given in the query. On Android, and for old SDK versions (<3) it
+ * will returned the app name suffixed by '(Outdated SDK)'.
+ *
+ * Reason is, in previous version (<3), app may not appear in correct device
+ * section because it refers to the name given by client which is not fixed
+ * for android emulators, so it is indicated as outdated so that developers
+ * might want to update SDK to get rid of this connection swap problem
+ * @param query A ClientQuery object.
+ */
+export function appNameWithUpdateHint(query: ClientQuery): string {
+  if (query.os === 'Android' && (!query.sdk_version || query.sdk_version < 3)) {
+    return query.app + ' (Outdated SDK)';
+  }
+  return query.app;
+}