refactor state handling to make application available independent of the state

src/application/ApplicationFactory.ts

@@ -0,0 +1,21 @@
+import { IApplication } from '@/domain/IApplication';
+import { AsyncLazy } from '@/infrastructure/Threading/AsyncLazy';
+import { IApplicationFactory } from './IApplicationFactory';
+import { parseApplication } from './Parser/ApplicationParser';
+
+export type ApplicationGetter = () => IApplication;
+const ApplicationGetter: ApplicationGetter = parseApplication;
+
+export class ApplicationFactory implements IApplicationFactory {
+    public static readonly Current: IApplicationFactory = new ApplicationFactory(ApplicationGetter);
+    private readonly getter: AsyncLazy<IApplication>;
+    protected constructor(costlyGetter: ApplicationGetter) {
+        if (!costlyGetter) {
+            throw new Error('undefined getter');
+        }
+        this.getter = new AsyncLazy<IApplication>(() => Promise.resolve(costlyGetter()));
+    }
+    public getAppAsync(): Promise<IApplication> {
+        return this.getter.getValueAsync();
+    }
+}