intercalateString function
Insert a String between other Strings and concatenate.
Implementation
String intercalateString(String s, Iterable<String> l) {
if (l.isEmpty) {
return '';
} else if (s.isEmpty) {
return concatStrings(l);
}
String result = '';
List<String> copy = List.from(l);
copy.removeLast();
for (var v in copy) {
result += (v + s);
}
result += l.last;
return result;
}