first commit

src/common/utils/cursor.util.spec.ts

@@ -0,0 +1,13 @@
+import { decodeOffsetCursor, encodeOffsetCursor } from './cursor.util';
+
+describe('cursor util', () => {
+  it('encodes and decodes cursor offsets', () => {
+    const cursor = encodeOffsetCursor(40);
+    expect(decodeOffsetCursor(cursor)).toBe(40);
+  });
+
+  it('returns null on invalid cursor', () => {
+    expect(decodeOffsetCursor('%%%invalid%%%')).toBeNull();
+    expect(decodeOffsetCursor(encodeOffsetCursor(-1))).toBeNull();
+  });
+});