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/main/protocol-handler/__test__/router.test.ts

@@ -1,7 +1,7 @@
 import { LensProtocolRouterMain } from "../router";
 import { noop } from "../../../common/utils";
-import { extensionsStore } from "../../../extensions/extensions-store";
-import { extensionLoader } from "../../../extensions/extension-loader";
+import { ExtensionsStore } from "../../../extensions/extensions-store";
+import { ExtensionLoader } from "../../../extensions/extension-loader";
 import * as uuid from "uuid";
 import { LensMainExtension } from "../../../extensions/core-api";
 import { broadcastMessage } from "../../../common/ipc";
@@ -16,20 +16,28 @@ function throwIfDefined(val: any): void {
 }
 
 describe("protocol router tests", () => {
-  let lpr: LensProtocolRouterMain;
-
   beforeEach(() => {
-    jest.clearAllMocks();
-    (extensionsStore as any).state.clear();
-    (extensionLoader as any).instances.clear();
-    LensProtocolRouterMain.resetInstance();
-    lpr = LensProtocolRouterMain.getInstance<LensProtocolRouterMain>();
+    ExtensionsStore.getInstanceOrCreate();
+    ExtensionLoader.getInstanceOrCreate();
+
+    const lpr = LensProtocolRouterMain.getInstanceOrCreate();
+
     lpr.extensionsLoaded = true;
     lpr.rendererLoaded = true;
   });
 
+  afterEach(() => {
+    jest.clearAllMocks();
+
+    ExtensionsStore.resetInstance();
+    ExtensionLoader.resetInstance();
+    LensProtocolRouterMain.resetInstance();
+  });
+
   it("should throw on non-lens URLS", async () => {
     try {
+      const lpr = LensProtocolRouterMain.getInstance();
+
       expect(await lpr.route("https://google.ca")).toBeUndefined();
     } catch (error) {
       expect(error).toBeInstanceOf(Error);
@@ -38,6 +46,8 @@ describe("protocol router tests", () => {
 
   it("should throw when host not internal or extension", async () => {
     try {
+      const lpr = LensProtocolRouterMain.getInstance();
+
       expect(await lpr.route("lens://foobar")).toBeUndefined();
     } catch (error) {
       expect(error).toBeInstanceOf(Error);
@@ -57,14 +67,15 @@ describe("protocol router tests", () => {
       isEnabled: true,
       absolutePath: "/foo/bar",
     });
+    const lpr = LensProtocolRouterMain.getInstance();
 
     ext.protocolHandlers.push({
       pathSchema: "/",
       handler: noop,
     });
 
-    (extensionLoader as any).instances.set(extId, ext);
-    (extensionsStore as any).state.set(extId, { enabled: true, name: "@mirantis/minikube" });
+    (ExtensionLoader.getInstance() as any).instances.set(extId, ext);
+    (ExtensionsStore.getInstance() as any).state.set(extId, { enabled: true, name: "@mirantis/minikube" });
 
     lpr.addInternalHandler("/", noop);
 
@@ -86,6 +97,7 @@ describe("protocol router tests", () => {
   });
 
   it("should call handler if matches", async () => {
+    const lpr = LensProtocolRouterMain.getInstance();
     let called = false;
 
     lpr.addInternalHandler("/page", () => { called = true; });
@@ -101,6 +113,7 @@ describe("protocol router tests", () => {
   });
 
   it("should call most exact handler", async () => {
+    const lpr = LensProtocolRouterMain.getInstance();
     let called: any = 0;
 
     lpr.addInternalHandler("/page", () => { called = 1; });
@@ -119,6 +132,7 @@ describe("protocol router tests", () => {
   it("should call most exact handler for an extension", async () => {
     let called: any = 0;
 
+    const lpr = LensProtocolRouterMain.getInstance();
     const extId = uuid.v4();
     const ext = new LensMainExtension({
       id: extId,
@@ -141,8 +155,8 @@ describe("protocol router tests", () => {
         handler: params => { called = params.pathname.id; },
       });
 
-    (extensionLoader as any).instances.set(extId, ext);
-    (extensionsStore as any).state.set(extId, { enabled: true, name: "@foobar/icecream" });
+    (ExtensionLoader.getInstance() as any).instances.set(extId, ext);
+    (ExtensionsStore.getInstance() as any).state.set(extId, { enabled: true, name: "@foobar/icecream" });
 
     try {
       expect(await lpr.route("lens://extension/@foobar/icecream/page/foob")).toBeUndefined();
@@ -155,6 +169,7 @@ describe("protocol router tests", () => {
   });
 
   it("should work with non-org extensions", async () => {
+    const lpr = LensProtocolRouterMain.getInstance();
     let called: any = 0;
 
     {
@@ -177,8 +192,8 @@ describe("protocol router tests", () => {
           handler: params => { called = params.pathname.id; },
         });
 
-      (extensionLoader as any).instances.set(extId, ext);
-      (extensionsStore as any).state.set(extId, { enabled: true, name: "@foobar/icecream" });
+      (ExtensionLoader.getInstance() as any).instances.set(extId, ext);
+      (ExtensionsStore.getInstance() as any).state.set(extId, { enabled: true, name: "@foobar/icecream" });
     }
 
     {
@@ -201,12 +216,12 @@ describe("protocol router tests", () => {
           handler: () => { called = 1; },
         });
 
-      (extensionLoader as any).instances.set(extId, ext);
-      (extensionsStore as any).state.set(extId, { enabled: true, name: "icecream" });
+      (ExtensionLoader.getInstance() as any).instances.set(extId, ext);
+      (ExtensionsStore.getInstance() as any).state.set(extId, { enabled: true, name: "icecream" });
     }
 
-    (extensionsStore as any).state.set("@foobar/icecream", { enabled: true, name: "@foobar/icecream" });
-    (extensionsStore as any).state.set("icecream", { enabled: true, name: "icecream" });
+    (ExtensionsStore.getInstance() as any).state.set("@foobar/icecream", { enabled: true, name: "@foobar/icecream" });
+    (ExtensionsStore.getInstance() as any).state.set("icecream", { enabled: true, name: "icecream" });
 
     try {
       expect(await lpr.route("lens://extension/icecream/page")).toBeUndefined();
@@ -219,10 +234,13 @@ describe("protocol router tests", () => {
   });
 
   it("should throw if urlSchema is invalid", () => {
+    const lpr = LensProtocolRouterMain.getInstance();
+
     expect(() => lpr.addInternalHandler("/:@", noop)).toThrowError();
   });
 
   it("should call most exact handler with 3 found handlers", async () => {
+    const lpr = LensProtocolRouterMain.getInstance();
     let called: any = 0;
 
     lpr.addInternalHandler("/", () => { called = 2; });
@@ -241,6 +259,7 @@ describe("protocol router tests", () => {
   });
 
   it("should call most exact handler with 2 found handlers", async () => {
+    const lpr = LensProtocolRouterMain.getInstance();
     let called: any = 0;
 
     lpr.addInternalHandler("/", () => { called = 2; });