Refactoring: move all code files into a src directory

src/UI/Base/AsyncLazy.ts

@@ -0,0 +1,26 @@
+import BaseUIElement from "../BaseUIElement"
+import { VariableUiElement } from "./VariableUIElement"
+import { Stores } from "../../Logic/UIEventSource"
+import Loading from "./Loading"
+
+export default class AsyncLazy extends BaseUIElement {
+    private readonly _f: () => Promise<BaseUIElement>
+
+    constructor(f: () => Promise<BaseUIElement>) {
+        super()
+        this._f = f
+    }
+
+    protected InnerConstructElement(): HTMLElement {
+        // The caching of the BaseUIElement will guarantee that _f will only be called once
+
+        return new VariableUiElement(
+            Stores.FromPromise(this._f()).map((el) => {
+                if (el === undefined) {
+                    return new Loading()
+                }
+                return el
+            })
+        ).ConstructElement()
+    }
+}