[refactor] Moved 'createPopup' to its own TS file.

utils/uiHelpers/createPopup.ts

@@ -0,0 +1,32 @@
+import { createElement } from "./createElement";
+
+/**
+ * Creates the necessary DOM elements to present an in-game popup to the player.
+ * @param id The (hopefully) unique identifier for the popup container.
+ * @param elems The collection of HTML Elements to show within the popup.
+ */
+export function createPopup(id: string, elems: HTMLElement[]) {
+    const container: HTMLDivElement = createElement("div", {
+            class: "popup-box-container",
+            display: "block",
+            id,
+        }) as HTMLDivElement;
+    const content: HTMLElement = createElement("div", {
+            class: "popup-box-content",
+            id: `${id}-content`,
+        });
+
+    for (const elem of elems) {
+        content.appendChild(elem);
+    }
+    container.appendChild(content);
+    const gameContainer: HTMLElement | null = document.getElementById("entire-game-container");
+
+    if (gameContainer === null) {
+        throw new Error("Unable to find the game container. Something is *seriously* wrong...");
+    }
+
+    gameContainer.appendChild(container);
+
+    return container;
+}