Username UI Improvements

Co-authored-by: Fedor Indutny <238531+indutny@users.noreply.github.com>

ts/util/splitText.ts

@@ -0,0 +1,46 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+export type SplitTextOptionsType = Readonly<{
+  granularity: 'grapheme' | 'word';
+  shouldBreak: (slice: string) => boolean;
+}>;
+
+export function splitText(
+  text: string,
+  { granularity, shouldBreak }: SplitTextOptionsType
+): Array<string> {
+  const isWordBased = granularity === 'word';
+  const segmenter = new Intl.Segmenter(undefined, {
+    granularity,
+  });
+
+  const result = new Array<string>();
+
+  // Compute number of lines and height of text
+  let acc = '';
+  let best = '';
+  for (const { segment, isWordLike } of segmenter.segment(text)) {
+    acc += segment;
+
+    // For "grapheme" segmenting, "isWordLike" is always "undefined"
+    if (isWordLike === false) {
+      best = acc;
+      continue;
+    }
+
+    if (shouldBreak(isWordBased ? acc.trim() : acc)) {
+      result.push(best);
+      acc = acc.slice(best.length);
+      best = acc;
+    } else {
+      best = acc;
+    }
+  }
+
+  if (best) {
+    result.push(best);
+  }
+
+  return isWordBased ? result.map(x => x.trim()) : result;
+}