truncate function
Truncate text to maxLen characters, appending ellipsis if truncated.
Implementation
String truncate(String text, int maxLen, {String ellipsis = '...'}) {
if (text.length <= maxLen) return text;
final end = maxLen - ellipsis.length;
if (end <= 0) return ellipsis.substring(0, maxLen);
return '${text.substring(0, end)}$ellipsis';
}