Bug: DefaultValue returned from selector get instead of actual default

[ayroblu]

I have the following code:

import { get, set } from "idb-keyval";
import type { AtomEffect } from "recoil";
import { DefaultValue, atom, selector } from "recoil";

export const syncIdbEffect =
  <T>(dbKey: string): AtomEffect<T> =>
  ({ onSet, setSelf }) => {
    setSelf(
      get(dbKey).then((savedVal: T | null) =>
        savedVal !== null || savedVal !== undefined ? savedVal : new DefaultValue(),
      ),
    );
    onSet((newVal, oldVal) => {
      if (newVal === oldVal) return;

      set(dbKey, newVal);
    });
  };

const tokenState = atom<string | undefined>({
  key: "tokenState",
  default: undefined,
  effects: [syncIdbEffect("token")],
});
export const isAuthedState = selector<boolean>({
  key: "isAuthedState",
  get: ({ get }) => {
    const refreshToken = get(tokenState);
    // MARK: At this stage refresh is of type "DefaultValue {}". TypeScript thinks that only string | undefined is the type
    return !!refreshToken;
  },
});

It's failing because the DefaultValue object is being returned from the get, where I'd expect the default to be undefined (see the MARK comment)

I'm using Recoil v0.7.6

[xotahal]

I believe this is a duplicity of https://github.com/facebookexperimental/Recoil/issues/2151

[xotahal]

This helped me - https://github.com/facebookexperimental/Recoil/issues/2151#issuecomment-1491111260

[mluiten]

I believe I'm experiencing this as well -- returning DefaultValue from a async (): Promise<T | DefaultValue> directly into setSelf will make it return DefaultValue, instead of the (explicitly set) default of undefined.

Seeing how this project no longer seems to be maintained, I'm starting the migration to jotai :(