to-apollo-store.ts

import { ApolloStore } from 'apollo-client';
import { Store } from '@ngrx/store';
import { skip } from 'rxjs/operator/skip';
import { take } from 'rxjs/operator/take';


export function toApolloStore(store: Store<any>): ApolloStore {
  return {
    subscribe(fn: () => void): () => void {
      const futureStates$ = skip.call(store, 1);
      const subscription = futureStates$.subscribe(() => fn());
      
      return () => subscription.unsubscribe();
    },
    getState(): any {
      let lastState;
      const lastState$ = take.call(store, 1);
      
      lastState$.subscribe(state => lastState = state);
      
      return lastState;
    },
    dispatch(action: any) {
      store.dispatch(action);
    }
  };
}