fix: garbled text displayed on avatars (#6575)

Co-authored-by: dwelle <luzar.david@gmail.com>

src/clients.ts

@@ -20,9 +20,13 @@ export const getClientColors = (clientId: string, appState: AppState) => {
   };
 };
 
-export const getClientInitials = (userName?: string | null) => {
-  if (!userName?.trim()) {
-    return "?";
-  }
-  return userName.trim()[0].toUpperCase();
+/**
+ * returns first char, capitalized
+ */
+export const getNameInitial = (name?: string | null) => {
+  // first char can be a surrogate pair, hence using codePointAt
+  const firstCodePoint = name?.trim()?.codePointAt(0);
+  return (
+    firstCodePoint ? String.fromCodePoint(firstCodePoint) : "?"
+  ).toUpperCase();
 };

src/components/Avatar.tsx

@@ -1,7 +1,7 @@
 import "./Avatar.scss";
 
 import React, { useState } from "react";
-import { getClientInitials } from "../clients";
+import { getNameInitial } from "../clients";
 
 type AvatarProps = {
   onClick: (e: React.MouseEvent<HTMLDivElement, MouseEvent>) => void;
@@ -12,7 +12,7 @@ type AvatarProps = {
 };
 
 export const Avatar = ({ color, onClick, name, src }: AvatarProps) => {
-  const shortName = getClientInitials(name);
+  const shortName = getNameInitial(name);
   const [error, setError] = useState(false);
   const loadImg = !error && src;
   const style = loadImg ? undefined : { background: color };

src/tests/clients.test.ts

@@ -1,44 +1,39 @@
-import { getClientInitials } from "../clients";
+import { getNameInitial } from "../clients";
 
 describe("getClientInitials", () => {
   it("returns substring if one name provided", () => {
-    const result = getClientInitials("Alan");
-    expect(result).toBe("A");
+    expect(getNameInitial("Alan")).toBe("A");
   });
 
   it("returns initials", () => {
-    const result = getClientInitials("John Doe");
-    expect(result).toBe("J");
+    expect(getNameInitial("John Doe")).toBe("J");
   });
 
   it("returns correct initials if many names provided", () => {
-    const result = getClientInitials("John Alan Doe");
-    expect(result).toBe("J");
+    expect(getNameInitial("John Alan Doe")).toBe("J");
   });
 
   it("returns single initial if 1 letter provided", () => {
-    const result = getClientInitials("z");
-    expect(result).toBe("Z");
+    expect(getNameInitial("z")).toBe("Z");
   });
 
   it("trims trailing whitespace", () => {
-    const result = getClientInitials("  q    ");
-    expect(result).toBe("Q");
+    expect(getNameInitial("  q    ")).toBe("Q");
   });
 
   it('returns "?" if falsey value provided', () => {
-    let result = getClientInitials("");
-    expect(result).toBe("?");
-
-    result = getClientInitials(undefined);
-    expect(result).toBe("?");
-
-    result = getClientInitials(null);
-    expect(result).toBe("?");
+    expect(getNameInitial("")).toBe("?");
+    expect(getNameInitial(undefined)).toBe("?");
+    expect(getNameInitial(null)).toBe("?");
   });
 
   it('returns "?" when value is blank', () => {
-    const result = getClientInitials(" ");
-    expect(result).toBe("?");
+    expect(getNameInitial(" ")).toBe("?");
+  });
+
+  it("works with multibyte strings", () => {
+    expect(getNameInitial("😀")).toBe("😀");
+    // but doesn't work with emoji ZWJ sequences
+    expect(getNameInitial("👨‍👩‍👦")).toBe("👨");
   });
 });