Refactor: Implement SmartCube renderer, improve UI styling, and fix gaps

node_modules/@gkucmierz/utils/spec/list-node.spec.mjs

@@ -0,0 +1,33 @@
+
+import { ListNode } from '../src/list-node.mjs';
+
+describe('ListNode', () => {
+  it('constructor', () => {
+    expect(new ListNode().val).toEqual(0);
+    expect(new ListNode().next).toEqual(null);
+    expect(new ListNode(123).val).toEqual(123);
+    expect(new ListNode(123).next).toEqual(null);
+    expect(new ListNode(123, 'next').next).toEqual('next');
+  });
+
+  it('toArr', () => {
+    expect(new ListNode().toArr()).toEqual([0]);
+    expect(new ListNode(123).toArr()).toEqual([123]);
+    expect(new ListNode(1, new ListNode(2)).toArr()).toEqual([1, 2]);
+  });
+
+  it('fromArr', () => {
+    expect(ListNode.fromArr([1, 2])).toEqual(new ListNode(1, new ListNode(2)));
+  });
+
+  it('both', () => {
+    const arr = [1, 2, 3, 4, 5];
+    expect(ListNode.fromArr(arr).toArr()).toEqual(arr);
+  });
+
+  it('cyclic reference', () => {
+    const node = ListNode.fromArr([1, 2]);
+    node.next.next = node;
+    expect(() => node.toArr()).toThrow(new Error('Cyclic reference detected'));
+  });
+});