fix(ui): keep diff refreshes targeted

2026-08-02 21:46:22 +03:00
parent 75832876fa
commit 17c2d5ec36
14 changed files with 268 additions and 38 deletions
@@ -0,0 +1,25 @@
+import { describe, expect, test } from 'bun:test';
+
+import { findDiffScrollAnchor, getRestoredDiffScrollTop } from './diffScrollAnchor';
+
+describe('diff scroll anchoring', () => {
+  test('uses the last file section that reached the top of the viewport', () => {
+    expect(findDiffScrollAnchor(100, [
+      { path: 'third.ts', top: 240 },
+      { path: 'second.ts', top: 80 },
+      { path: 'first.ts', top: -200 },
+    ])).toEqual({ path: 'second.ts', topOffset: -20 });
+  });
+
+  test('uses the first section when no header reached the viewport top yet', () => {
+    expect(findDiffScrollAnchor(100, [
+      { path: 'first.ts', top: 140 },
+      { path: 'second.ts', top: 300 },
+    ])).toEqual({ path: 'first.ts', topOffset: 40 });
+  });
+
+  test('restores the prior section offset and clamps at the scroll boundary', () => {
+    expect(getRestoredDiffScrollTop(500, -20, 80, 1000)).toBe(600);
+    expect(getRestoredDiffScrollTop(950, -20, 80, 1000)).toBe(1000);
+  });
+});