fix(react-avatar): support initials calculation for GB18030-2022 extension characters (#35878)

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: dmytrokirpa

change/@fluentui-react-avatar-b3b582c1-9dae-4459-9787-66b6167b0458.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "fix: support initials calculation for GB18030-2022 extension characters",
+  "packageName": "@fluentui/react-avatar",
+  "email": "dmytrokirpa@microsoft.com",
+  "dependentChangeType": "patch"
+}

packages/react-components/react-avatar/library/src/utils/getInitials.test.ts

@@ -106,6 +106,26 @@ describe('getInitials', () => {
     expect(result).toEqual('');
   });
 
+  it('calculates initials for GB18030-2022 extension characters (CJK Ext B-I)', () => {
+    // These characters are encoded as surrogate pairs; the character itself should be returned as the initial
+    expect(getInitials('𬸚', false)).toEqual('𬸚'); // GFZB-196
+    expect(getInitials('𢃾', false)).toEqual('𢃾'); // CJK Ext B
+    expect(getInitials('𪜀', false)).toEqual('𪜀'); // CJK Ext C
+    expect(getInitials('𫜴', false)).toEqual('𫜴'); // CJK Ext C
+    expect(getInitials('𫟰', false)).toEqual('𫟰'); // CJK Ext D
+    expect(getInitials('𬺠', false)).toEqual('𬺠'); // CJK Ext E
+    expect(getInitials('𮓇', false)).toEqual('𮓇'); // CJK Ext F
+    expect(getInitials('𪛝', false)).toEqual('𪛝'); // BX
+    expect(getInitials('𰉖', false)).toEqual('𰉖'); // GX
+    expect(getInitials('𱘍', false)).toEqual('𱘍'); // HX
+    expect(getInitials('𮯰', false)).toEqual('𮯰'); // IX
+  });
+
+  it('calculates initials for mixed strings starting with GB18030-2022 extension characters', () => {
+    // First code point of a mixed string should be used as the initial
+    expect(getInitials('𫚭齅䶱5𮯠灋𬘭r𫟼蝌龯𪛒𪛛㊣𫜹⾢Ｚ𱔟𫍲𮴋䶺𰆬a', false)).toEqual('𫚭');
+  });
+
   it('calculates an expected initials for Japanese names', () => {
     let result = getInitials('松田', false);
     expect(result).toEqual('');

packages/react-components/react-avatar/library/src/utils/getInitials.ts

@@ -10,9 +10,11 @@ const UNWANTED_ENCLOSURES_REGEX: RegExp = /[\(\[\{][^\)\]\}]*[\)\]\}]/g;
 
 /**
  * Regular expression matching special ASCII characters except space, plus some unicode special characters.
- * Applies after unwanted enclosures have been removed
+ * Applies after unwanted enclosures have been removed.
+ * Note: the range starts at \uE000 (not \uD800) to avoid matching surrogate code units, which would break
+ * supplementary Unicode characters (encoded as surrogate pairs in UTF-16) such as GB18030-2022 extension characters.
  */
-const UNWANTED_CHARS_REGEX: RegExp = /[\0-\u001F\!-/:-@\[-`\{-\u00BF\u0250-\u036F\uD800-\uFFFF]/g;
+const UNWANTED_CHARS_REGEX: RegExp = /[\0-\u001F\!-/:-@\[-`\{-\u00BF\u0250-\u036F\uE000-\uFFFF]/g;
 
 /**
  * Regular expression matching phone numbers. Applied after chars matching UNWANTED_CHARS_REGEX have been removed
@@ -28,30 +30,43 @@ const MULTIPLE_WHITESPACES_REGEX: RegExp = /\s+/g;
  * Arabic:   Arabic, Arabic Supplement, Arabic Extended-A.
  * Korean:   Hangul Jamo, Hangul Compatibility Jamo, Hangul Jamo Extended-A, Hangul Syllables, Hangul Jamo Extended-B.
  * Japanese: Hiragana, Katakana.
- * CJK:      CJK Unified Ideographs Extension A, CJK Unified Ideographs, CJK Compatibility Ideographs,
- *             CJK Unified Ideographs Extension B
+ * CJK:      CJK Unified Ideographs Extension A, CJK Unified Ideographs, CJK Compatibility Ideographs.
+ * Note: Supplementary CJK characters (GB18030-2022 extension characters in Ext B-I) are intentionally not listed
+ * here so they can be rendered as initials.
  */
 const UNSUPPORTED_TEXT_REGEX: RegExp =
-  /[\u0600-\u06FF\u0750-\u077F\u08A0-\u08FF\u1100-\u11FF\u3130-\u318F\uA960-\uA97F\uAC00-\uD7AF\uD7B0-\uD7FF\u3040-\u309F\u30A0-\u30FF\u3400-\u4DBF\u4E00-\u9FFF\uF900-\uFAFF]|[\uD840-\uD869][\uDC00-\uDED6]/;
+  /[\u0600-\u06FF\u0750-\u077F\u08A0-\u08FF\u1100-\u11FF\u3130-\u318F\uA960-\uA97F\uAC00-\uD7AF\uD7B0-\uD7FF\u3040-\u309F\u30A0-\u30FF\u3400-\u4DBF\u4E00-\u9FFF\uF900-\uFAFF]/;
+
+function getFirstCodePoint(value: string): string {
+  if (!value) {
+    return '';
+  }
+
+  const codePoint = value.codePointAt(0);
+  return codePoint === undefined ? '' : String.fromCodePoint(codePoint);
+}
 
 function getInitialsLatin(displayName: string, isRtl: boolean, firstInitialOnly?: boolean): string {
   let initials = '';
 
   const splits: string[] = displayName.split(' ');
   if (splits.length !== 0) {
-    initials += splits[0].charAt(0).toUpperCase();
+    // Use code point-aware helper to correctly handle supplementary characters (e.g. GB18030-2022 extension chars)
+    // that are encoded as surrogate pairs; charAt(0) would only return half of such a character.
+    initials += getFirstCodePoint(splits[0]).toUpperCase();
   }
 
   if (!firstInitialOnly) {
     if (splits.length === 2) {
-      initials += splits[1].charAt(0).toUpperCase();
+      initials += getFirstCodePoint(splits[1]).toUpperCase();
     } else if (splits.length === 3) {
-      initials += splits[2].charAt(0).toUpperCase();
+      initials += getFirstCodePoint(splits[2]).toUpperCase();
     }
   }
 
-  if (isRtl && initials.length > 1) {
-    return initials.charAt(1) + initials.charAt(0);
+  if (isRtl && [...initials].length > 1) {
+    const chars = [...initials];
+    return chars[1] + chars[0];
   }
 
   return initials;
@@ -95,9 +110,12 @@ export function getInitials(
 
   displayName = cleanupDisplayName(displayName);
 
-  // For names containing CJK characters, and phone numbers, we don't display initials
+  // Check only the first code point against UNSUPPORTED_TEXT_REGEX so that names starting with a supported
+  // character (e.g. GB18030-2022 extension characters) produce an initial even when the rest of the string
+  // contains BMP CJK characters that would otherwise trigger the regex.
+  const firstCodePoint = getFirstCodePoint(displayName);
   if (
-    UNSUPPORTED_TEXT_REGEX.test(displayName) ||
+    UNSUPPORTED_TEXT_REGEX.test(firstCodePoint) ||
     (!options?.allowPhoneInitials && PHONENUMBER_REGEX.test(displayName))
   ) {
     return '';