thread node id through toHtml for deterministic+unique export ids

renderNode now passes the Craft node id as toHtml's 3rd argument
(props, childrenHtml, nodeId). Backward compatible: the resolver map is
untyped (any), so existing 2-arg toHtml implementations/tests are
unaffected. Adds scopeId()/stableHash() helpers in utils/escape.ts:
scopeId derives a scope string from the node id (deterministic AND
unique, since Craft node ids are unique per node and stable across
repeated exports of the same page) with a stableHash(seed) fallback for
legacy call sites without a node id.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

craft/src/utils/escape.test.ts

@@ -1,5 +1,5 @@
 import { describe, test, expect } from 'vitest';
-import { escapeHtml, escapeAttr, safeUrl } from './escape';
+import { escapeHtml, escapeAttr, safeUrl, stableHash, scopeId } from './escape';
 
 describe('escapeHtml', () => {
   test('escapes &, <, >, "', () => {
@@ -93,3 +93,50 @@ describe('safeUrl', () => {
     expect(safeUrl('https://x.com/a?b=1&c=2')).toBe('https://x.com/a?b=1&c=2');
   });
 });
+
+describe('stableHash', () => {
+  test('same input always produces the same output', () => {
+    expect(stableHash('hello')).toBe(stableHash('hello'));
+  });
+
+  test('different inputs produce different output (no collision for these cases)', () => {
+    expect(stableHash('hello')).not.toBe(stableHash('world'));
+  });
+
+  test('returns a non-empty string', () => {
+    expect(stableHash('')).toEqual(expect.any(String));
+    expect(stableHash('x').length).toBeGreaterThan(0);
+  });
+});
+
+describe('scopeId', () => {
+  test('same node id -> identical scope id across calls (deterministic)', () => {
+    expect(scopeId('node-abc', 'seed', 'sb')).toBe(scopeId('node-abc', 'seed', 'sb'));
+  });
+
+  test('different node ids -> different, non-colliding scope ids even with the same fallback seed', () => {
+    const id1 = scopeId('node-a', 'same-seed', 'sb');
+    const id2 = scopeId('node-b', 'same-seed', 'sb');
+    expect(id1).not.toBe(id2);
+  });
+
+  test('node id is slugified (non-alphanumeric characters stripped, lowercased)', () => {
+    expect(scopeId('Node ID! 123', 'seed', 'sb')).toBe('sb_nodeid123');
+  });
+
+  test('no nodeId (legacy 2-arg call sites) falls back to a deterministic hash of the seed, not Math.random', () => {
+    const id1 = scopeId(undefined, 'same-seed', 'sb');
+    const id2 = scopeId(undefined, 'same-seed', 'sb');
+    expect(id1).toBe(id2);
+  });
+
+  test('no nodeId: different seeds fall back to different hashes', () => {
+    const id1 = scopeId(undefined, 'seed-one', 'sb');
+    const id2 = scopeId(undefined, 'seed-two', 'sb');
+    expect(id1).not.toBe(id2);
+  });
+
+  test('prefix is applied', () => {
+    expect(scopeId('node-abc', 'seed', 'tabs')).toMatch(/^tabs_/);
+  });
+});

craft/src/utils/escape.ts

@@ -89,3 +89,44 @@ export function slugId(s: string | undefined, fallback = 'field'): string {
   const base = (s || '').toString().toLowerCase().replace(/[^a-z0-9]+/g, '-').replace(/^-+|-+$/g, '');
   return base || fallback;
 }
+
+/**
+ * Deterministic (non-cryptographic) string hash -- djb2. Same input always
+ * produces the same output across export runs (pure function of the
+ * string, no Math.random/Date.now). Used as a fallback seed source when a
+ * Craft node id isn't available -- see `scopeId` below.
+ */
+export function stableHash(seed: string): string {
+  let h = 5381;
+  for (let i = 0; i < seed.length; i++) {
+    h = ((h << 5) + h + seed.charCodeAt(i)) | 0;
+  }
+  return (h >>> 0).toString(36);
+}
+
+/**
+ * Derives a deterministic AND unique per-node scope id for a component's
+ * exported element ids / aria-controls / aria-labelledby / for / inline
+ * `<script>` function names.
+ *
+ * Craft.js assigns every node in a serialized page tree a unique id that
+ * is stable across repeated exports of the same saved page. Scoping ids on
+ * that node id -- rather than `Math.random()` (unique but changes on every
+ * export, breaking caching/diffing) or a hash of prop/content data
+ * (deterministic but COLLIDES whenever two instances share default or
+ * identical content) -- yields ids that are simultaneously deterministic
+ * (same node -> same id, every export) and collision-free (different
+ * nodes -> different ids, even with identical content).
+ *
+ * `nodeId` is optional only for defensive/legacy call sites -- existing
+ * `toHtml(props, childrenHtml)` 2-arg callers that haven't been updated to
+ * pass the node id. In that case we fall back to `stableHash(fallbackSeed)`,
+ * which is still deterministic (never Math.random) but, like the old
+ * per-component hash implementations, can collide across instances with
+ * identical content. Callers should always pass the real node id when
+ * available.
+ */
+export function scopeId(nodeId: string | undefined, fallbackSeed: string, prefix: string): string {
+  const slug = (nodeId || '').toString().toLowerCase().replace(/[^a-z0-9]+/g, '');
+  return `${prefix}_${slug || stableHash(fallbackSeed)}`;
+}

craft/src/utils/html-export.ts

@@ -74,10 +74,19 @@ function renderNode(nodes: Record<string, any>, nodeId: string): { html: string
   // Build data attributes for responsive visibility and animations
   const dataAttrs = buildDataAttrs(props);
 
-  // Look up component in resolver and call toHtml
+  // Look up component in resolver and call toHtml. `nodeId` is the Craft.js
+  // node id for this node -- unique per node in the tree and stable across
+  // repeated exports of the same saved page. It's passed as a 3rd argument
+  // so components can derive deterministic AND unique scope ids for their
+  // exported element ids / aria-wiring / inline-script function names
+  // (see `scopeId` in utils/escape.ts) instead of Math.random() (unique but
+  // non-deterministic) or a content hash (deterministic but collides when
+  // two instances share default/identical content). Components that don't
+  // need a scope id simply ignore the extra argument -- backward compatible
+  // with existing 2-arg `toHtml(props, childrenHtml)` implementations/tests.
   const component = resolver[typeName];
   if (component && typeof component.toHtml === 'function') {
-    const result = component.toHtml(props, allChildrenHtml);
+    const result = component.toHtml(props, allChildrenHtml, nodeId);
     const html = result.html || '';
     return { html: injectAttrs(html, dataAttrs) };
   }