description

# 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.

## Implementation

    String join([String separator = ""]) {
      Iterator<E> iterator = this.iterator;
      if (!iterator.moveNext()) return "";
      StringBuffer buffer = StringBuffer();
      if (separator == null || separator == "") {
        do {
          buffer.write(iterator.current.toString());
        } while (iterator.moveNext());
      } else {
        buffer.write(iterator.current.toString());
        while (iterator.moveNext()) {
          buffer.write(separator);
          buffer.write(iterator.current.toString());
        }
      }
      return buffer.toString();
    }