Fixing Singleton typing to correctly return child class (#1914)

- Add distinction between `getInstance` and `getInstanceOrCreate` since
  it is not always possible to create an instance (since you might not
  know the correct arguments)

- Remove all the `export const *Store = *Store.getInstance<*Store>();`
  calls as it defeats the purpose of `Singleton`. Plus with the typing
  changes the appropriate `*Store.getInstance()` is "short enough".

- Special case the two extension export facades to not need to use
  `getInstanceOrCreate`. Plus since they are just facades it is always
  possible to create them.

- Move some other types to be also `Singleton`'s: ExtensionLoader,
  ExtensionDiscovery, ThemeStore, LocalizationStore, ...

- Fixed dev-run always using the same port with electron inspect

- Update Store documentation with new recommendations about creating
  instances of singletons

- Fix all unit tests to create their dependent singletons

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

src/extensions/__tests__/extension-discovery.test.ts

@@ -1,6 +1,7 @@
 import { watch } from "chokidar";
 import { join, normalize } from "path";
 import { ExtensionDiscovery, InstalledExtension } from "../extension-discovery";
+import { ExtensionsStore } from "../extensions-store";
 
 jest.mock("../../common/ipc");
 jest.mock("fs-extra");
@@ -17,6 +18,12 @@ jest.mock("../extension-installer", () => ({
 const mockedWatch = watch as jest.MockedFunction<typeof watch>;
 
 describe("ExtensionDiscovery", () => {
+  beforeEach(() => {
+    ExtensionDiscovery.resetInstance();
+    ExtensionsStore.resetInstance();
+    ExtensionsStore.getInstanceOrCreate();
+  });
+
   it("emits add for added extension", async done => {
     globalThis.__non_webpack_require__.mockImplementation(() => ({
       name: "my-extension"
@@ -36,7 +43,7 @@ describe("ExtensionDiscovery", () => {
     mockedWatch.mockImplementationOnce(() =>
       (mockWatchInstance) as any
     );
-    const extensionDiscovery = new ExtensionDiscovery();
+    const extensionDiscovery = ExtensionDiscovery.getInstanceOrCreate();
 
     // Need to force isLoaded to be true so that the file watching is started
     extensionDiscovery.isLoaded = true;
@@ -76,7 +83,7 @@ describe("ExtensionDiscovery", () => {
     mockedWatch.mockImplementationOnce(() =>
       (mockWatchInstance) as any
     );
-    const extensionDiscovery = new ExtensionDiscovery();
+    const extensionDiscovery = ExtensionDiscovery.getInstanceOrCreate();
 
     // Need to force isLoaded to be true so that the file watching is started
     extensionDiscovery.isLoaded = true;

src/extensions/__tests__/extension-loader.test.ts

@@ -1,15 +1,21 @@
 import { ExtensionLoader } from "../extension-loader";
 import { ipcRenderer } from "electron";
-import { extensionsStore } from "../extensions-store";
+import { ExtensionsStore } from "../extensions-store";
+import { Console } from "console";
+import { stdout, stderr } from "process";
+
+console = new Console(stdout, stderr);
 
 const manifestPath = "manifest/path";
 const manifestPath2 = "manifest/path2";
 const manifestPath3 = "manifest/path3";
 
 jest.mock("../extensions-store", () => ({
-  extensionsStore: {
-    whenLoaded: Promise.resolve(true),
-    mergeState: jest.fn()
+  ExtensionsStore: {
+    getInstance: () => ({
+      whenLoaded: Promise.resolve(true),
+      mergeState: jest.fn()
+    })
   }
 }));
 
@@ -99,8 +105,12 @@ jest.mock(
 );
 
 describe("ExtensionLoader", () => {
-  it("renderer updates extension after ipc broadcast", async (done) => {
-    const extensionLoader = new ExtensionLoader();
+  beforeEach(() => {
+    ExtensionLoader.resetInstance();
+  });
+
+  it.only("renderer updates extension after ipc broadcast", async (done) => {
+    const extensionLoader = ExtensionLoader.getInstanceOrCreate();
 
     expect(extensionLoader.userExtensions).toMatchInlineSnapshot(`Map {}`);
 
@@ -140,20 +150,20 @@ describe("ExtensionLoader", () => {
   });
 
   it("updates ExtensionsStore after isEnabled is changed", async () => {
-    (extensionsStore.mergeState as any).mockClear();
+    (ExtensionsStore.getInstance().mergeState as any).mockClear();
 
     // Disable sending events in this test
     (ipcRenderer.on as any).mockImplementation();
 
-    const extensionLoader = new ExtensionLoader();
+    const extensionLoader = ExtensionLoader.getInstanceOrCreate();
 
     await extensionLoader.init();
 
-    expect(extensionsStore.mergeState).not.toHaveBeenCalled();
+    expect(ExtensionsStore.getInstance().mergeState).not.toHaveBeenCalled();
 
     Array.from(extensionLoader.userExtensions.values())[0].isEnabled = false;
 
-    expect(extensionsStore.mergeState).toHaveBeenCalledWith({
+    expect(ExtensionsStore.getInstance().mergeState).toHaveBeenCalledWith({
       "manifest/path": {
         enabled: false,
         name: "TestExtension"

src/extensions/__tests__/lens-extension.test.ts

@@ -1,4 +1,8 @@
 import { LensExtension } from "../lens-extension";
+import { Console } from "console";
+import { stdout, stderr } from "process";
+
+console = new Console(stdout, stderr);
 
 let ext: LensExtension = null;