Support a module API surface for custom functionality (#8246)

* Early implementation of module API surface + functions for ILAG module

* Wire up dialog functions and ILAG-needed surface

* Ensure component renders for modules get overridden

* Respond to changes from module API interface

* Use a real module-api dependency

* Update for new Dialogs interface

* Add support for getConfigValue from module API

* Update the remainder of the module API interface

* Docs & cleanup

* Add some unit tests around module stuff

Needs end-to-end tests still.

* Appease early linters

* Break import cycles by not directly depending on Lifecycle

* Appease the linter

* Fix bad merge

test/modules/ProxiedModuleApi-test.ts

@@ -0,0 +1,79 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { TranslationStringsObject } from "@matrix-org/react-sdk-module-api/lib/types/translations";
+
+import { ProxiedModuleApi } from "../../src/modules/ProxiedModuleApi";
+import { stubClient } from "../test-utils";
+import { setLanguage } from "../../src/languageHandler";
+import { ModuleRunner } from "../../src/modules/ModuleRunner";
+import { registerMockModule } from "./MockModule";
+
+describe("ProxiedApiModule", () => {
+    afterEach(() => {
+        ModuleRunner.instance.reset();
+    });
+
+    // Note: Remainder is implicitly tested from end-to-end tests of modules.
+
+    describe("translations", () => {
+        it("should cache translations", () => {
+            const api = new ProxiedModuleApi();
+            expect(api.translations).toBeFalsy();
+
+            const translations: TranslationStringsObject = {
+                ["custom string"]: {
+                    "en": "custom string",
+                    "fr": "custom french string",
+                },
+            };
+            api.registerTranslations(translations);
+            expect(api.translations).toBe(translations);
+        });
+
+        describe("integration", () => {
+            it("should translate strings using translation system", async () => {
+                // Test setup
+                stubClient();
+
+                // Set up a module to pull translations through
+                const module = registerMockModule();
+                const en = "custom string";
+                const de = "custom german string";
+                const enVars = "custom variable %(var)s";
+                const varVal = "string";
+                const deVars = "custom german variable %(var)s";
+                const deFull = `custom german variable ${varVal}`;
+                expect(module.apiInstance).toBeInstanceOf(ProxiedModuleApi);
+                module.apiInstance.registerTranslations({
+                    [en]: {
+                        "en": en,
+                        "de": de,
+                    },
+                    [enVars]: {
+                        "en": enVars,
+                        "de": deVars,
+                    },
+                });
+                await setLanguage("de"); // calls `registerCustomTranslations()` for us
+
+                // See if we can pull the German string out
+                expect(module.apiInstance.translateString(en)).toEqual(de);
+                expect(module.apiInstance.translateString(enVars, { var: varVal })).toEqual(deFull);
+            });
+        });
+    });
+});