forwardRef

In the following example, Person is defined before Father but relies on Father. In this case, you should use forwardRef to wrap Father. Otherwise redi would receive undefined when tries to figure out dependencies of Person (and it would throw an error in that case).

import { Self, SkipSelf, Optional } from "@wendellhu/redi";
 
class Person {
  constructor(
    @SkipSelf() @Optional(forwardRef(() => Father)) readonly father: Father,
  ) { }
}
 
class Father extends Person {
  changeDiaper(): void { }
}
 
const parentInjector = new Injector([[Person], [Father, { useFactory: f => f, deps: [Person] }]])
const injector = parentInjector.createChild([[Person]]);
const person = injector.get(Person);
expect(person.father).toBe(parentInjector.get(Person)); // true

💡

This is not related to redi itself but how TypeScript is transpiled into JavaScript.

Hierarchy Injection System Using in React