join method Null safety

String join(
  1. [String separator = ""]

Converts each element to a String and concatenates the strings.

Iterates through elements of this iterable, converts each one to a String by calling Object.toString, and then concatenates the strings, with the separator string interleaved between the elements.


final planetsByMass = <double, String>{0.06: 'Mercury', 0.81: 'Venus',
  0.11: 'Mars'};
final joinedNames = planetsByMass.values.join('-'); // Mercury-Venus-Mars


String join([String separator = ""]) {
  if (length == 0) return "";
  StringBuffer buffer = StringBuffer()..writeAll(this, separator);
  return buffer.toString();