effects.js

import { createStore, effect } from 'easy-peasy'; // 👈 import the helper

const store = createStore({
  session: {
    user: undefined,
    // 👇 define your effectful action
    login: effect(async (dispatch, payload, getState) => {
      const user = await loginService(payload)
      dispatch.session.loginSucceeded(user)
    }),
    loginSucceeded: (state, payload) => {
      state.user = payload
    }
  }
});