Selectors in state with discriminated union type

[Binek115]

I often define a state using discriminated union type. When using whole state in template it is straightforward since if provide correct type inference.

type State = { type: 'loading' } | { type: 'loaded'; value: number[] };

@if (state.type === 'loading') {
  loading
} @else {
  {{ state.value }}
}

However I am not sure how to deal with selectors. I think about defining state as nullable for other states but I am not sure if it is the best solution since it need another if in order to check for null values which whould not be possible according to state.

export class Store extends ComponentStore<State> {
  readonly value = this.select((state) => (state.type === 'loaded' ? state.value.filter((x) => x > 5) : null));
}

Alternative approach for it is to not define state as discriminated union type but rather something like

type State = { type: 'loading' | 'loaded'; value: number[] };

but it makes impossible state possible.
Another solution I thought of was to not use selectors at all but rather pure state + e.g. pipes in order to manipulate data.
Is there a better solution for this kind of problems?