I am using angular2dart and want to know, why do I have to pass keyword const on:
directives: const [HeroDetailComponent]
const means a compile-time constant. Been constant it can be optimized and instantiated only once.
const [HeroDetailComponent] means that the list is a compile time constant. Compile-time constants are mandatory when used as metadata (in your case
directives is a named parameter of
@Component() that is a metadata of your class).