Hierarchical injectors

Creating hierarchical injectors

There are two ways to create parenting relationship between two injectors. The first approach is to callcreateChild method on the parent injector:

const parentInjector = new Injector([[PlatformService]]);
const childInjector = parentInjector.createChild([[OrderService]]);

The second is to pass the parent injector as the second parameter when constructing an new injector:

const parentInjector = new Injector([[PlatformService]]);
const childInjector = new Injector([[OrderService]], parentInjector);

Single way lookup

When the child injector could not resolve an identifier, it would delegate the request to its parent if possible. And that is called dependency lookup. In the example below, PlatformService is actually constructed by parentInjector.

childInjector.get(PlatformService);

Interfere lookup

You could tell redi how to perform the lookup process using specific decorators. You could use SkipSelf to skip the current injector, or Self to disable lookup:

class ChartComponent {
  constructor(
    @Self() @Inject(Container) private readonly selfContainer: Container,
    @SkipSelf()
    @Optional(Container)
    private readonly parentContainer?: Container,
  ) {}
}