feat: normalize search text (#14449)

#### PR Dependency Tree


* **PR #14449** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Improvements**
* Search text normalization now applied consistently across doc titles,
search results, and highlights for uniform display formatting.

* **Tests**
* Added comprehensive test coverage for search text normalization
utility.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/utils/__tests__/normalize-search-text.spec.ts

@@ -0,0 +1,33 @@
+import { expect, test } from 'vitest';
+
+import { normalizeSearchText } from '../normalize-search-text';
+
+test('normalizeSearchText should keep plain text unchanged', () => {
+  expect(normalizeSearchText('hello world')).toBe('hello world');
+});
+
+test('normalizeSearchText should decode serialized single-item array', () => {
+  expect(normalizeSearchText('["hello world"]')).toBe('hello world');
+});
+
+test('normalizeSearchText should decode serialized highlighted array', () => {
+  expect(normalizeSearchText('["<b>hello</b> world"]')).toBe(
+    '<b>hello</b> world'
+  );
+});
+
+test('normalizeSearchText should join serialized multi-item array', () => {
+  expect(normalizeSearchText('["hello","world"]')).toBe('hello world');
+});
+
+test('normalizeSearchText should decode serialized string', () => {
+  expect(normalizeSearchText('"hello world"')).toBe('hello world');
+});
+
+test('normalizeSearchText should keep invalid serialized text unchanged', () => {
+  expect(normalizeSearchText('["hello"')).toBe('["hello"');
+});
+
+test('normalizeSearchText should support array input', () => {
+  expect(normalizeSearchText(['hello', 'world'])).toBe('hello world');
+});

packages/frontend/core/src/utils/index.ts

@@ -2,6 +2,7 @@ export * from './channel';
 export * from './create-emotion-cache';
 export * from './event';
 export * from './extract-emoji-icon';
+export * from './normalize-search-text';
 export * from './string2color';
 export * from './toast';
 export * from './unflatten-object';

packages/frontend/core/src/utils/normalize-search-text.ts

@@ -0,0 +1,62 @@
+interface NormalizeSearchTextOptions {
+  fallback?: string;
+  arrayJoiner?: string;
+}
+
+function tryParseSerializedText(value: string): unknown | null {
+  const trimmed = value.trim();
+  if (!trimmed) {
+    return null;
+  }
+
+  // Indexer/storage may serialize text arrays as JSON strings like ["foo"].
+  if (!trimmed.startsWith('[') && !trimmed.startsWith('"')) {
+    return null;
+  }
+
+  try {
+    return JSON.parse(trimmed);
+  } catch {
+    return null;
+  }
+}
+
+export function normalizeSearchText(
+  value: unknown,
+  { fallback = '', arrayJoiner = ' ' }: NormalizeSearchTextOptions = {}
+): string {
+  if (value === null || value === undefined) {
+    return fallback;
+  }
+
+  if (Array.isArray(value)) {
+    const normalized = value
+      .map(item =>
+        normalizeSearchText(item, {
+          fallback: '',
+          arrayJoiner,
+        })
+      )
+      .filter(Boolean);
+
+    return normalized.length > 0 ? normalized.join(arrayJoiner) : fallback;
+  }
+
+  if (typeof value !== 'string') {
+    return String(value);
+  }
+
+  const parsed = tryParseSerializedText(value);
+  if (parsed === null) {
+    return value;
+  }
+
+  if (typeof parsed === 'string' || Array.isArray(parsed)) {
+    return normalizeSearchText(parsed, {
+      fallback,
+      arrayJoiner,
+    });
+  }
+
+  return value;
+}