ngrx/entity for whole state or part

Question

I'm not sure I understand @ngrx/entity package. There are of course examples but I didn't found any with a state bigger than one property/subject.

So before using @ngrx/entity my sub state look like below. Yes it's actually a sub state. That means that I've separation per feature but still it isn't single property interface. I have a few model interfaces and State consists of them. Those that are arrays I want to replace with 'entity features'. And from examples I see that Entity is for the whole state?

export interface ListItems {
}

export interface FooObject {
}

export interface State {
  property1: ListItems[];
  others: FooObject[];
  name: string;
  isLoading: boolean;
  error: string;
}

So to use Enity should I do?

export interface State extends EntityState<?> {
}

And what should I put in place of ? I have many properties.

or

each model interface ListItems, FooObject should extends EntityState ?

score 0 · Answer 1 · answered Mar 29 '20 at 11:44

0

By the design if FooObject is an entity and ListItems is an entity you should have 2 separate EntityAdapters for them. Because EntityState is responsible to manage a single entity.

instead of property1: ListItems[]; and others: FooObject[] I would recommend to store ids only string[] or number[].

here you can find an example how to mange several types of entities with @ngrx/entity: https://github.com/satanTime/ngrx-entity-relationship/blob/master/e2e/angular9/src/app/store/user/user.reducer.ts https://github.com/satanTime/ngrx-entity-relationship/blob/master/e2e/angular9/src/app/store/address/address.reducer.ts

Later in code you can select the loading flag, and once it has been finished to get its ids and to select ListItems and FooObject via withLatestFrom rxjs operator.

answered Mar 29 '20 at 11:44

satanTime

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I still don't understand part that - I have defined State and in that state two properties are array. We know what problem arrays have. So I need EntityState there. But looks like EntityState force me to split my State and extract arrays as separate state. This sound ridiculous. In that case every array will be a separate state plus big file to handle that. So I'm confused and even don't want to try before consulting with someone. – userbb Mar 30 '20 at 16:58
if you want to store something more than an entity (2 arrays of entities) simply use normal reducers and you can set the state there exactly as the State above is. – satanTime Mar 30 '20 at 18:15
@userbb, let me know if you need help with the question. For example let's share a code sample and the goal you want to achieve there. – satanTime Mar 31 '20 at 11:00

score 0 · Answer 2 · answered Apr 07 '20 at 06:54

You can't use more than one entityAdapter / state interface, because the entity adapter is typed for that interface. You can add some extra fields but no more arrays in one slice of the state. EX:

export interface MyEntity {
  id: string;
  name: string;
}

export interface MyEntityState extends EntityState<MyEntity> {
  // Additional props
  loading: boolean;
  loaded: boolean;
}

export const adapter: EntityAdapter<MyEntity> = createEntityAdapter<MyEntity>();

const _initialState = adapter.getInitialState({
  loading: false,
  loaded: false
})

...

ngrx/entity for whole state or part

2 Answers2