如何通过 id 从 ngrx-entity 商店中选择唯一实体

Question

I have in my ngrx-entity store the prsnls entity well described as array of objects as shown in redux devtool.

I'm able to select all prsnl entities like this:

export const selectAllPrsnls = createSelector(
    selectPrsnlState,
    prsnlsState => {
        const allPrsnls = Object.values(prsnlsState.entities)
        return allPrsnls;
    }
);

But I'm unable to get a unique prsnl by it's id. This is what I did:

export const selectUniquePrsnls = (id:string) => createSelector(
    selectPrsnlState,
    prsnlsState => {
        const uniquePrsnls = Object.values(prsnlsState.entities[id])
        return uniquePrsnls;
    }
  );

The unique prsnl is not fetched because when I console.log after susbscribing to the createSelector observable, I get undefined in the console. This is how I subscribed to it:

getUniquePersnlValues(id:string){
    this.store
    .pipe(select(selectUniquePrsnls), map((per) => per))
    .subscribe((value: any) => this.uniquePrsnl = value);
    console.log('prsnl', this.uniquePrsnl);
  }

I think I'm not able to troubleshoot this issue because I don't understand well what does the selectPrsnlState when creating the selector like on srrenshot:

How can I then get a unique prsnl from the prsnls entities in this situation. Any help is much appreciated. Thanks in advance.

Answer 1

You can get element by id like this:

export const selectUniquePrsnls = (id:string) => createSelector(
    selectPrsnlState,
    prsnlsState => prsnlsState.entities[id]
  );