truncate method
Truncates to maxLength chars, appending ellipsis if cut.
'Hello World'.truncate(7); // 'Hell...'
Implementation
String truncate(int maxLength, {String ellipsis = '...'}) {
assert(
maxLength > ellipsis.length,
'maxLength must exceed ellipsis length',
);
if (length <= maxLength) return this;
return substring(0, maxLength - ellipsis.length) + ellipsis;
}