generate method Null safety

String generate(
  1. {Map<String, dynamic>? options}
)

v4() Generates a RNG version 4 UUID

By default it will generate a string based mathRNG, and will return a string. If you wish to use crypto-strong RNG, pass in UuidUtil.cryptoRNG

The first argument is an options map that takes various configuration options detailed in the readme.

http://tools.ietf.org/html/rfc4122.html#section-4.4

Implementation

String generate({Map<String, dynamic>? options}) {
  options ??= {};

  // Use the built-in RNG or a custom provided RNG
  List positionalArgs = options['positionalArgs'] ?? [];
  Map<Symbol, dynamic> namedArgs = options['namedArgs'] ?? const <Symbol, dynamic>{};
  List<int> rng = (options['rng'] != null) ? Function.apply(options['rng'], positionalArgs, namedArgs) : globalRNG();

  // Use provided values over RNG
  List<int> rnds = options['random'] ?? rng;

  // per 4.4, set bits for version and clockSeq high and reserved
  rnds[6] = (rnds[6] & 0x0f) | 0x40;
  rnds[8] = (rnds[8] & 0x3f) | 0x80;

  return UuidParsing.unparse(rnds);
}