fix(ui): stabilize Markdown code block line layout (#2444)

* fix(ui): stabilize markdown code block layout * fix(ui): respect text range boundary affinity * test(ui): cover trailing text range boundaries
2026-07-26 20:40:33 +03:00
parent b6cdf7b6a7
commit e52d692ac0
10 changed files with 289 additions and 146 deletions
@@ -0,0 +1,87 @@
+import { afterEach, describe, expect, test } from 'bun:test';
+
+import { copyMarkdownToClipboard } from './clipboard';
+
+const originalNavigator = Object.getOwnPropertyDescriptor(globalThis, 'navigator');
+const originalClipboardItem = Object.getOwnPropertyDescriptor(globalThis, 'ClipboardItem');
+
+const restoreGlobal = (name: 'navigator' | 'ClipboardItem', descriptor?: PropertyDescriptor): void => {
+  if (descriptor) {
+    Object.defineProperty(globalThis, name, descriptor);
+  } else {
+    Reflect.deleteProperty(globalThis, name);
+  }
+};
+
+afterEach(() => {
+  restoreGlobal('navigator', originalNavigator);
+  restoreGlobal('ClipboardItem', originalClipboardItem);
+});
+
+describe('copyMarkdownToClipboard', () => {
+  test('offers rich HTML and Markdown source in one clipboard item', async () => {
+    let writtenItem: { data: Record<string, Blob> } | undefined;
+    class FakeClipboardItem {
+      static supports(type: string): boolean {
+        return type === 'text/markdown';
+      }
+
+      readonly data: Record<string, Blob>;
+
+      constructor(data: Record<string, Blob>) {
+        this.data = data;
+      }
+    }
+
+    Object.defineProperty(globalThis, 'ClipboardItem', { configurable: true, value: FakeClipboardItem });
+    Object.defineProperty(globalThis, 'navigator', {
+      configurable: true,
+      value: {
+        clipboard: {
+          write: async (items: Array<{ data: Record<string, Blob> }>) => {
+            writtenItem = items[0];
+          },
+        },
+      },
+    });
+
+    const result = await copyMarkdownToClipboard('**bold**', '<p><strong>bold</strong></p>');
+
+    expect(result).toEqual({ ok: true, method: 'clipboard' });
+    expect(Object.keys(writtenItem?.data ?? {}).sort()).toEqual(['text/html', 'text/markdown', 'text/plain']);
+    expect(await writtenItem?.data['text/plain']?.text()).toBe('**bold**');
+    expect(await writtenItem?.data['text/markdown']?.text()).toBe('**bold**');
+    expect(await writtenItem?.data['text/html']?.text()).toBe('<p><strong>bold</strong></p>');
+  });
+
+  test('falls back to plain Markdown when a rich clipboard write fails', async () => {
+    let fallbackText = '';
+    class FakeClipboardItem {
+      static supports(): boolean {
+        return false;
+      }
+
+      constructor() {}
+    }
+
+    Object.defineProperty(globalThis, 'ClipboardItem', { configurable: true, value: FakeClipboardItem });
+    Object.defineProperty(globalThis, 'navigator', {
+      configurable: true,
+      value: {
+        clipboard: {
+          write: async () => {
+            throw new Error('unsupported');
+          },
+          writeText: async (text: string) => {
+            fallbackText = text;
+          },
+        },
+      },
+    });
+
+    const result = await copyMarkdownToClipboard('# title', '<h1>title</h1>');
+
+    expect(result).toEqual({ ok: true, method: 'clipboard' });
+    expect(fallbackText).toBe('# title');
+  });
+});