description

# join method

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.

Example:

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

## Implementation

    String join([String separator = ""]) {
      Iterator<E> iterator = this.iterator;
      if (!iterator.moveNext()) return "";
      var first = iterator.current.toString();
      if (!iterator.moveNext()) return first;
      var buffer = StringBuffer(first);
      // TODO(51681): Drop null check when de-supporting pre-2.12 code.
      if (separator == null || separator.isEmpty) {
        do {
          buffer.write(iterator.current.toString());
        } while (iterator.moveNext());
      } else {
        do {
          buffer
            ..write(separator)
            ..write(iterator.current.toString());
        } while (iterator.moveNext());
      }
      return buffer.toString();
    }