Zod for Validating Models

import { Injectable } from "@angular/core";
import { Actions, concatLatestFrom, createEffect, ofType } from "@ngrx/effects";
import { Store } from "@ngrx/store";
import { catchError, filter, map, of, tap } from "rxjs";
import { z } from "zod";
import { selectCountData } from "..";
import { CounterCommands, CounterDocuments } from "../actions/count-actions";
import { CountState } from "../reducers/count-reducer";

@Injectable()
export class CounterDataEffects {
  private readonly COUNT_DATA_KEY = "count-data";

  private readonly CountDataSchema = z.object({
    current: z.number(),

    by: z.union([z.literal(1), z.literal(3), z.literal(5)]),
  }); // CounterCommandsLoad => ?? => CounterDocuments.counter

  loadCountData$ = createEffect(
    () => {
      return this.actions$.pipe(
        ofType(CounterCommands.load), // we only care about this action
        map(() => localStorage.getItem(this.COUNT_DATA_KEY)),
        filter((x) => !!x), // stop here if we don't have anything in local storage
        map((stringy) => JSON.parse(stringy || "{}") as CountState), // try to parse it with a dummy object to make TS happy
        map((obj) => this.CountDataSchema.parse(obj) as CountState), // Zod parse, will throw if it isn't.
        map((data) => CounterDocuments.counter({ payload: data })),
        catchError((err) =>
          of({
            type: "error",
            source: "counter-prefs",
            message: "we have ourselves a hacker here!",
            payload: err,
          })
        )
      );
    },
    { dispatch: true }
  );

  saveCountData$ = createEffect(
    () => {
      return this.actions$.pipe(
        ofType(
          CounterCommands.countby,
          CounterCommands.decremented,
          CounterCommands.incremented,
          CounterCommands.reset
        ), // stop here if it isn't one of these.

        concatLatestFrom(() => this.store.select(selectCountData)), // => subscribed observable of our data returned from selectCountData

        map(([, data]) => JSON.stringify(data)), // turn that data into a string so I can write it local storage

        tap((data) => localStorage.setItem(this.COUNT_DATA_KEY, data)) // write that sucker to localstorage
      );
    },
    { dispatch: false }
  ); // whatever emerges here has to be action, and it is sent to the store.

  constructor(private actions$: Actions, private store: Store) {}
}