isOptional property
bool isOptionalReturns true
if the reflectee is an optional parameter. Otherwise returns false
.
Source
bool get isOptional;
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/1.24.3/dart-mirrors/ParameterMirror/isOptional.html