mode_edit codeAPI / @angular/coreInjectFlagslinkenum 稳定Injection flags for DI.enum InjectFlags { Default: 0b0000 Host: 0b0001 Self: 0b0010 SkipSelf: 0b0100 Optional: 0b1000 }成员列表link成员值说明Default0b0000Host0b0001Specifies that an injector should retrieve a dependency from any injector until reaching the host element of the current component. (Only used with Element Injector)Self0b0010Don't descend into ancestors of the node requesting injection.SkipSelf0b0100Skip the node that is requesting injection.Optional0b1000Inject defaultValue instead if token not found.