join static method

String join(String part1, String part2, [ String? part3, String? part4, String? part5, ])

Joins path parts using the appropriate platform separator.

Implementation

static String join(
  String part1,
  String part2, [
  String? part3,
  String? part4,
  String? part5,
]) {
  final separator = Platform.isWindows ? r'\' : '/';

  String trimPart(String p) {
    var s = p;
    while (s.startsWith('/') || s.startsWith(r'\')) {
      s = s.substring(1);
    }
    while (s.endsWith('/') || s.endsWith(r'\')) {
      s = s.substring(0, s.length - 1);
    }
    return s;
  }

  var base = part1;
  while (base.length > 1 && (base.endsWith('/') || base.endsWith(r'\'))) {
    base = base.substring(0, base.length - 1);
  }

  final parts = [part2, part3, part4, part5].whereType<String>();
  for (final part in parts) {
    final trimmed = trimPart(part);
    if (trimmed.isNotEmpty) {
      if (base.isEmpty) {
        base = trimmed;
      } else if (base.endsWith(separator)) {
        base = '$base$trimmed';
      } else {
        base = '$base$separator$trimmed';
      }
    }
  }
  return base;
}