extensions property
Arbitrary additions to this theme.
This is the same property as extensions in ThemeData, it is provided as a convenience pass-through to ThemeData.
To define extensions, pass an Iterable containing one or more
ThemeExtension
subclasses to ThemeData.new or copyWith.
To obtain an extension, use ThemeData.of(context).extension.
Implementation
final Iterable<ThemeExtension<dynamic>>? extensions;