Introduce typing for extension API to prevent breakage

Signed-off-by: Sebastian Malton <sebastian@malton.name>

src/extensions/common-api/app.ts

@@ -11,11 +11,25 @@ import isWindowsInjectable from "../../common/vars/is-windows.injectable";
 import { asLegacyGlobalFunctionForExtensionApi } from "../as-legacy-globals-for-extension-api/as-legacy-global-function-for-extension-api";
 import { getLegacyGlobalDiForExtensionApi } from "../as-legacy-globals-for-extension-api/legacy-global-di-for-extension-api";
 import getEnabledExtensionsInjectable from "./get-enabled-extensions/get-enabled-extensions.injectable";
-import * as Preferences from "./user-preferences";
+import type { UserPreferenceExtensionItems } from "./user-preferences";
+import { Preferences } from "./user-preferences";
 import { slackUrl, issuesTrackerUrl } from "../../common/vars";
 import { buildVersionInjectionToken } from "../../common/vars/build-semantic-version.injectable";
 
-const App = {
+export interface AppExtensionItems {
+  readonly Preferences: UserPreferenceExtensionItems;
+  readonly version: string;
+  readonly appName: string;
+  readonly slackUrl: string;
+  readonly issuesTrackerUrl: string;
+  readonly isSnap: boolean;
+  readonly isWindows: boolean;
+  readonly isMac: boolean;
+  readonly isLinux: boolean;
+  getEnabledExtensions: () => string[];
+}
+
+export const App: AppExtensionItems = {
   Preferences,
   getEnabledExtensions: asLegacyGlobalFunctionForExtensionApi(getEnabledExtensionsInjectable),
   get version() {
@@ -51,5 +65,3 @@ const App = {
   slackUrl,
   issuesTrackerUrl,
 };
-
-export default App;

src/extensions/common-api/index.ts

@@ -4,7 +4,7 @@
  */
 
 // APIs
-import App from "./app";
+import { App } from "./app";
 import * as EventBus from "./event-bus";
 import * as Store from "./stores";
 import * as Util from "./utils";

src/extensions/common-api/user-preferences.ts

@@ -4,10 +4,13 @@
  */
 
 import { UserStore } from "../../common/user-store";
-
-/**
+export interface UserPreferenceExtensionItems {
+  /**
    * Get the configured kubectl binaries path.
    */
-export function getKubectlPath(): string | undefined {
-  return UserStore.getInstance().kubectlBinariesPath;
+  getKubectlPath: () => string | undefined;
 }
+
+export const Preferences: UserPreferenceExtensionItems = {
+  getKubectlPath: () => UserStore.getInstance().kubectlBinariesPath,
+};