rtrim function
Removes the given chars from the end of the string.
If chars is null, trailing whitespace is removed.
Example:
rtrim('hello '); // 'hello'
rtrim('helloxx', 'x'); // 'hello'
Implementation
String rtrim(String str, [String? chars]) {
if (chars == null) return str.trimRight();
final set = chars.split('').toSet();
var end = str.length;
while (end > 0 && set.contains(str[end - 1])) {
end--;
}
return str.substring(0, end);
}