operator + method
Implementation
StringJoiner operator +(final value) {
if (value is Iterable) {
value.forEach((v) => this + v);
return this;
}
if (value == null || value == '') return this;
String s = '';
if (value is String) {
s = value;
} else {
s = value.toString();
}
if (s.isEmpty) return this;
if (str.isNotEmpty) str += join;
str += s;
return this;
}