typescript tuple in class heritance, lost types

Question

how i can override a class array with tuple and add native instance in index and keep the types ?

how i can make this valid, what can be the correct syntax ?

playground: playground

class Base {
    protected children?:Base[]
}
class Containers extends Base {
    protected override children:Array<Containers|Primitives>; 
}

class Primitives extends Base {
}

class A extends Containers {
 // so children should automaticly someting like : [A,A,B,...Containers|Primitives] ?
    protected override children:[A,A,B]
    init(){
        const i0 = this.children[0];
        const i1 = this.children[1]; 
        const i2 = this.children[2]; 
        const i3 = this.children[3]; // should Containers|Primitives|undefined because extends Containers ?
    }

}
class B extends Containers {

}

So in this code A can have native instance in children index, where i use getter . But ...rest of children should auto herite parent Containers|Primitives no ?

Also this is weird , if i remove type, everything became instance A ?!!

EDIT: I see i can write like this ! protected override children:[A,...Array<Containers|Primitives>] But i repeat code from parent class, is there a good way to avoid repeat ?

Answer 1

class Base {
    protected children?: Base[]
}
class Containers extends Base {
    // let say, container entity can have childrens (Containers|Primitives)
    protected override children: Array<Containers | Primitives> = [];
}

class Primitives extends Base {
}

class A extends Containers {
    // Let say A have some native instance in children [A,A,B,...Containers|Primitives]
    protected override children: [A, A, B, ...Containers[] | Primitives[]] = [new A(), new A(), new B()];
    init() {
        const i0 = this.children[0];
        const i1 = this.children[1];
        const i2 = this.children[2];
        const i3 = this.children[3]; // // Primitives | Containers
    }

}
class B extends Containers {

}

You need to use spread syntax

[A,A,B,...Containers|Primitives] does not compile because you are allowed to use ... only with arrays

Playground

children is referenced directly or indirectly in its own initializer, so explicit type annotation is required