Using React Redux Toolkit with Typescript – set state for reducer

I’m trying to use React Redux Toolkit with TypeScript and I’m facing this issue with the creation of the reducer for the User model.

This is my userReducer.ts file:

import { createReducer } from "@reduxjs/toolkit";
import { UserModel } from "../../models/UserModel";
import {setUser, getUser, removeUser} from "../actions/userActions";

const initialState: UserModel = {
  email: "",
  id: "",
}

export const userReducer = createReducer(initialState, (builder) =>
  builder
    .addCase(getUser, (state) => state)
    .addCase(removeUser, () => initialState)
    .addCase(setUser, (state, action) => { ...state, ...action.payload })
);

I’m having issues with the last addCase for setting the user, intellisense says:

A spread argument must either have a tuple type or be passed to a rest parameter.ts(2556)
Cannot find name 'state'.ts(2304)

I don’t understand how to fix it and more in general how to set the state properly using Redux with Typescript.

>Solution :

I suppose you want to return state updated with action.payload?:

 .addCase(setUser, (state, action) => ({ ...state, ...action.payload }))