when<TResult extends Object?> method

  1. @optionalTypeArgs
TResult when<TResult extends Object?>({
  1. required TResult file(
    1. File file
    ),
  2. required TResult network(
    1. String url
    ),
})

A switch-like method, using callbacks.

As opposed to map, this offers destructuring. It is equivalent to doing:

switch (sealedClass) {
  case Subclass(:final field):
    return ...;
  case Subclass2(:final field2):
    return ...;
}

Implementation

@optionalTypeArgs TResult when<TResult extends Object?>({required TResult Function( File file)  file,required TResult Function( String url)  network,}) {final _that = this;
switch (_that) {
case XXFile():
return file(_that.file);case XXImage():
return network(_that.url);}
}