feat: some refactoring and cleanup

lib/Rung.ts

@@ -0,0 +1,34 @@
+export type RungOptions = {};
+
+export default abstract class Rung {
+    protected el: HTMLElement | null = null;
+
+    protected constructor(options: RungOptions) {}
+
+    render(): HTMLElement {
+        if (!this.el) {
+            this.el = this.build();
+        }
+        return this.el;
+    }
+
+    protected getEl(): HTMLElement {
+        return this.render();
+    }
+
+    redraw(): void {
+        const oldNode = this.el;
+        if (!oldNode || !this.el) {
+            return;
+        }
+        const parent = this.el.parentElement;
+        if (parent) {
+            this.el = this.build();
+            parent.replaceChild(this.el, oldNode);
+        } else {
+            this.render();
+        }
+    }
+
+    protected abstract build(): HTMLElement;
+}