feat(lab): createDiffFile builds a DiffViewer file from two versions of a text

.changeset/diff-viewer-catalog-keys.md

@@ -0,0 +1,7 @@
+---
+'@astryxdesign/core': patch
+---
+
+[feat] Adds the `@astryx.diffViewer.*` keys to the `en` catalog so the lab `DiffViewer` reads its file-status badges, line counts, line-number button labels, per-line "Added"/"Removed" labels, and empty-state messages from the translation runtime. No existing string changes; locales without a translation fall back to English.
+
+@latxh

apps/storybook/stories/DiffViewer.stories.tsx

@@ -0,0 +1,267 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.
+
+import type {Meta, StoryObj} from '@storybook/react';
+import {useState} from 'react';
+import {
+  DiffViewer,
+  createDiffFile,
+  parseUnifiedDiff,
+  type DiffViewerLineRef,
+} from '@astryxdesign/lab';
+import {Button} from '@astryxdesign/core/Button';
+import {Card} from '@astryxdesign/core/Card';
+import {CheckboxInput} from '@astryxdesign/core/CheckboxInput';
+import {HStack, StackItem, VStack} from '@astryxdesign/core/Stack';
+import {Text} from '@astryxdesign/core/Text';
+
+const PATCH = `diff --git a/src/cart/total.ts b/src/cart/total.ts
+index 4c1a2b7..9e0f3d1 100644
+--- a/src/cart/total.ts
++++ b/src/cart/total.ts
+@@ -1,16 +1,18 @@
+ import type {CartItem} from './types';
++import {roundCurrency} from '../money';
+
+ /**
+- * Sum the price of every item in the cart.
++ * Sum the price of every item in the cart, applying the discount once
++ * after the subtotal so rounding errors do not compound per item.
+  */
+-export function cartTotal(items: CartItem[], discount = 0) {
+-  let total = 0;
+-  for (const item of items) {
+-    total += item.price * item.quantity * (1 - discount);
+-  }
+-  return total;
++export function cartTotal(items: CartItem[], discount = 0): number {
++  const subtotal = items.reduce(
++    (sum, item) => sum + item.price * item.quantity,
++    0,
++  );
++  return roundCurrency(subtotal * (1 - discount));
+ }
+
+ export function isEmpty(items: CartItem[]) {
+   return items.length === 0;
+ }
+@@ -40,7 +42,7 @@ export function formatTotal(total: number, currency: string) {
+   const formatter = new Intl.NumberFormat(undefined, {
+     style: 'currency',
+     currency,
+-    maximumFractionDigits: 3,
++    maximumFractionDigits: 2,
+   });
+   return formatter.format(total);
+ }
+diff --git a/src/money.ts b/src/money.ts
+new file mode 100644
+index 0000000..b3f1c2e
+--- /dev/null
++++ b/src/money.ts
+@@ -0,0 +1,4 @@
++/** Round to whole cents. */
++export function roundCurrency(value: number): number {
++  return Math.round(value * 100) / 100;
++}
+diff --git a/src/cart/legacy.ts b/src/cart/legacyTotals.ts
+similarity index 100%
+rename from src/cart/legacy.ts
+rename to src/cart/legacyTotals.ts
+diff --git a/public/receipt.png b/public/receipt.png
+index 1f2e3d4..5a6b7c8 100644
+Binary files a/public/receipt.png and b/public/receipt.png differ
+`;
+
+const FILES = parseUnifiedDiff(PATCH);
+const [TOTAL_FILE] = FILES;
+
+const meta: Meta<typeof DiffViewer> = {
+  title: 'Lab/DiffViewer',
+  component: DiffViewer,
+  tags: ['autodocs'],
+  parameters: {
+    layout: 'padded',
+  },
+  args: {
+    file: TOTAL_FILE,
+  },
+  decorators: [
+    Story => (
+      <div style={{maxWidth: 1080, padding: 16}}>
+        <Story />
+      </div>
+    ),
+  ],
+};
+
+export default meta;
+type Story = StoryObj<typeof DiffViewer>;
+
+/** One file, unified view (the default). */
+export const Default: Story = {};
+
+/** Old file on the start side, new file on the end side. */
+export const Split: Story = {
+  args: {viewMode: 'split'},
+};
+
+/** Long lines wrap instead of scrolling. */
+export const Wrapped: Story = {
+  args: {viewMode: 'split', isWrapped: true},
+  decorators: [
+    Story => (
+      <div style={{maxWidth: 720}}>
+        <Story />
+      </div>
+    ),
+  ],
+};
+
+/** A whole patch: one DiffViewer per file, incl. added, renamed, and binary files. */
+export const MultiFilePatch: Story = {
+  render: args => (
+    <VStack gap={3}>
+      {FILES.map(file => (
+        <DiffViewer key={file.newPath ?? file.oldPath} {...args} file={file} />
+      ))}
+    </VStack>
+  ),
+};
+
+/** Diff two versions of a text with createDiffFile. */
+export const FromTwoTexts: Story = {
+  args: {
+    file: createDiffFile({
+      path: 'config/flags.yaml',
+      oldValue: [
+        'flags:',
+        '  checkout_v2: false',
+        '  dark_mode: true',
+        '  search_suggestions: false',
+        '  # owner: payments',
+        '  retries: 3',
+      ].join('\n'),
+      newValue: [
+        'flags:',
+        '  checkout_v2: true',
+        '  dark_mode: true',
+        '  search_suggestions: false',
+        '  # owner: payments',
+        '  retries: 5',
+        '  timeout_ms: 2000',
+      ].join('\n'),
+    }),
+  },
+};
+
+/** File header actions: a "Viewed" checkbox that also folds the file away. */
+export const ViewedToggle: Story = {
+  render: args => {
+    const [isViewed, setIsViewed] = useState(false);
+    const [isCollapsed, setIsCollapsed] = useState(false);
+    return (
+      <DiffViewer
+        {...args}
+        isCollapsed={isCollapsed}
+        onCollapsedChange={setIsCollapsed}
+        headerEnd={
+          <CheckboxInput
+            label="Viewed"
+            value={isViewed}
+            onChange={checked => {
+              setIsViewed(checked);
+              setIsCollapsed(checked);
+            }}
+          />
+        }
+      />
+    );
+  },
+};
+
+interface Comment {
+  id: number;
+  side: DiffViewerLineRef['side'];
+  lineNumber: number;
+}
+
+/**
+ * Review comments: click a line number to open a comment under that line.
+ * Anchors (side + lineNumber) stay put when switching view modes.
+ */
+export const ReviewComments: Story = {
+  render: args => {
+    const [viewMode, setViewMode] = useState<'unified' | 'split'>('unified');
+    const [comments, setComments] = useState<Comment[]>([
+      {id: 1, side: 'new', lineNumber: 13},
+    ]);
+    return (
+      <VStack gap={3}>
+        <HStack gap={2} vAlign="center">
+          <StackItem size="fill">
+            <Text type="supporting" color="secondary">
+              Click a line number to add a comment.
+            </Text>
+          </StackItem>
+          <Button
+            label={viewMode === 'unified' ? 'Split view' : 'Unified view'}
+            variant="secondary"
+            onClick={() =>
+              setViewMode(mode => (mode === 'unified' ? 'split' : 'unified'))
+            }
+          />
+        </HStack>
+        <DiffViewer
+          {...args}
+          viewMode={viewMode}
+          onLineNumberClick={ref =>
+            setComments(current => [
+              ...current,
+              {id: Date.now(), side: ref.side, lineNumber: ref.lineNumber},
+            ])
+          }
+          renderLineAnnotation={ref => {
+            const here = comments.filter(
+              comment =>
+                comment.side === ref.side &&
+                comment.lineNumber === ref.lineNumber,
+            );
+            if (here.length === 0) {
+              return null;
+            }
+            return (
+              <VStack gap={2}>
+                {here.map(comment => (
+                  <Card key={comment.id}>
+                    <HStack gap={2} vAlign="center">
+                      <StackItem size="fill">
+                        <Text>
+                          {`Comment on ${comment.side} line ${comment.lineNumber}`}
+                        </Text>
+                      </StackItem>
+                      <Button
+                        label="Resolve"
+                        variant="ghost"
+                        size="sm"
+                        onClick={() =>
+                          setComments(current =>
+                            current.filter(c => c.id !== comment.id),
+                          )
+                        }
+                      />
+                    </HStack>
+                  </Card>
+                ))}
+              </VStack>
+            );
+          }}
+        />
+      </VStack>
+    );
+  },
+};
+
+/** Without line numbers, capped height. */
+export const Compact: Story = {
+  args: {hasLineNumbers: false, maxHeight: 240},
+};

internal/shadcn-registry/routes.lock.json

@@ -556,6 +556,11 @@
       "path": "components/lab/code-editor",
       "aliases": []
     },
+    {
+      "name": "component-lab-diff-viewer",
+      "path": "components/lab/diff-viewer",
+      "aliases": []
+    },
     {
       "name": "component-lab-drawer",
       "path": "components/lab/drawer",
@@ -4255,6 +4260,11 @@
       "path": "showcases/dialog/default",
       "aliases": []
     },
+    {
+      "name": "showcase-diff-viewer-unified-diff-from-a-patch",
+      "path": "showcases/diff-viewer/unified-diff-from-a-patch",
+      "aliases": []
+    },
     {
       "name": "showcase-divider-variants",
       "path": "showcases/divider/variants",

packages/core/locales/en.json

@@ -527,6 +527,82 @@
     "defaultMessage": "This {itemName} is already {boundary, select, first {first} last {last} other {}}.",
     "description": "Screen-reader-only live announcement when an arrow-key reorder attempt has no effect because the record is already at that end of the list. `{itemName}` is the consumer's singular noun for one record; `{boundary}` is always exactly \"first\" or \"last\"."
   },
+  "@astryx.diffViewer.label": {
+    "defaultMessage": "Diff",
+    "description": "Accessible name of a lab DiffViewer's scrollable code area when the file has no path to name it."
+  },
+  "@astryx.diffViewer.renamedPath": {
+    "defaultMessage": "{oldPath} → {newPath}",
+    "description": "File path shown in a lab DiffViewer header when the file was renamed. `{oldPath}` and `{newPath}` are file paths and must stay untranslated; keep the arrow pointing from the old path to the new one."
+  },
+  "@astryx.diffViewer.statusAdded": {
+    "defaultMessage": "Added",
+    "description": "Badge in a lab DiffViewer file header marking a file that the change creates."
+  },
+  "@astryx.diffViewer.statusDeleted": {
+    "defaultMessage": "Deleted",
+    "description": "Badge in a lab DiffViewer file header marking a file that the change removes."
+  },
+  "@astryx.diffViewer.statusRenamed": {
+    "defaultMessage": "Renamed",
+    "description": "Badge in a lab DiffViewer file header marking a file that the change moves to a new path."
+  },
+  "@astryx.diffViewer.addedCount": {
+    "defaultMessage": "+{count, number}",
+    "description": "Compact count of added lines shown in a lab DiffViewer file header, e.g. \"+12\". Hidden from screen readers, which hear `@astryx.diffViewer.stats` instead."
+  },
+  "@astryx.diffViewer.removedCount": {
+    "defaultMessage": "−{count, number}",
+    "description": "Compact count of removed lines shown in a lab DiffViewer file header, e.g. \"−3\" (a minus sign). Hidden from screen readers, which hear `@astryx.diffViewer.stats` instead."
+  },
+  "@astryx.diffViewer.stats": {
+    "defaultMessage": "{added, plural, one {# line added} other {# lines added}}, {removed, plural, one {# line removed} other {# lines removed}}",
+    "description": "Screen-reader text for the line counts in a lab DiffViewer file header, e.g. \"12 lines added, 3 lines removed\"."
+  },
+  "@astryx.diffViewer.added": {
+    "defaultMessage": "Added",
+    "description": "Screen-reader text marking one line of a lab DiffViewer as added by the change; sighted readers see a + sign and a tinted row."
+  },
+  "@astryx.diffViewer.removed": {
+    "defaultMessage": "Removed",
+    "description": "Screen-reader text marking one line of a lab DiffViewer as removed by the change; sighted readers see a - sign and a tinted row."
+  },
+  "@astryx.diffViewer.lineNumberButton": {
+    "defaultMessage": "{side, select, old {Original line {line, number}} other {Changed line {line, number}}}",
+    "description": "Accessible label of a clickable line number in a lab DiffViewer (callers use it, for example, to start a comment on that line). `side` is `old` for the file before the change and `new` for the file after it; `line` is the line number in that version."
+  },
+  "@astryx.diffViewer.columnOldLine": {
+    "defaultMessage": "Original line number",
+    "description": "Screen-reader-only header of a lab DiffViewer column holding line numbers in the file before the change. Pairs with `@astryx.diffViewer.lineNumberButton` (\"Original line …\")."
+  },
+  "@astryx.diffViewer.columnNewLine": {
+    "defaultMessage": "Changed line number",
+    "description": "Screen-reader-only header of a lab DiffViewer column holding line numbers in the file after the change. Pairs with `@astryx.diffViewer.lineNumberButton` (\"Changed line …\")."
+  },
+  "@astryx.diffViewer.columnChange": {
+    "defaultMessage": "Change",
+    "description": "Screen-reader-only header of a lab DiffViewer column that marks each line as added or removed (noun: the kind of change)."
+  },
+  "@astryx.diffViewer.columnCode": {
+    "defaultMessage": "Code",
+    "description": "Screen-reader-only header of the source-code column in a lab DiffViewer's single-column (unified) view."
+  },
+  "@astryx.diffViewer.columnOldCode": {
+    "defaultMessage": "Original code",
+    "description": "Screen-reader-only header of the source-code column for the file before the change, in a lab DiffViewer's side-by-side (split) view."
+  },
+  "@astryx.diffViewer.columnNewCode": {
+    "defaultMessage": "Changed code",
+    "description": "Screen-reader-only header of the source-code column for the file after the change, in a lab DiffViewer's side-by-side (split) view."
+  },
+  "@astryx.diffViewer.binary": {
+    "defaultMessage": "Binary file not shown",
+    "description": "Message in place of line changes in a lab DiffViewer when the file is binary and has no text diff."
+  },
+  "@astryx.diffViewer.noChanges": {
+    "defaultMessage": "No content changes",
+    "description": "Message in a lab DiffViewer when a file changed only its path or mode, so there are no line changes to show."
+  },
   "@astryx.markdownHeadingLinks.copied": {
     "defaultMessage": "Link copied",
     "description": "Accessible name on the Markdown heading copy button and text announced to a polite live region for ~1.5s after a successful copy. Sentence meaning \"Link copied\"; pairs with `markdownHeadingLinks.copy`."