Error: Trying to access a property that is not defined (reference to 'user')

Question

Error: Trying to access a property that is not defined (reference to 'user')

import { createSlice } from '@reduxjs/toolkit';

export const userSlice = createSlice({
  name: 'user',
  initialState: {
    user: null,
  },
  // The `reducers` field allows us to define reducers and generate associated actions
  reducers: {
    login: (state, action) => {
      state.user = action.payload;
    },
    logout: (state) => {
      state.user = null;
    },
  },
  
  });
  
export const { login, logout } = userSlice.actions;

export const selectUser = (state) => state.user.user;



export default userSlice.reducer;

Error: userSlice.js:22 Uncaught TypeError: Cannot read properties of undefined (reading 'user') at selectUser (userSlice.js:22:1)

javascript html css reactjs redux

Answer 1

Answer №1

To retrieve the user, it is necessary to utilize configureStore along with useSelector.

Step 1:

You can create a new file called store or give it any desired name.

import { configureStore } from "@reduxjs/toolkit";
import User from "./slices/userSlice";

const store = configureStore({
 reducer: {
  User: User,
 },
});

export default store;

Step 2:

In the index.js file, you need to include the provider as shown below:

import React from "react";
import ReactDOM from "react-dom/client";
import App from "./App";
import { Provider } from "react-redux";
import store from "./store/index";

const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(
 <Provider store={store}>
  <App />
 </Provider>
);

Step 3:

Utilize useSelector to access the user from anywhere in this manner:

const user = useSelector((state) => state.User.user); 
console.log(user);

Answer 2

To retrieve the user, it is necessary to utilize configureStore along with useSelector.

Step 1:

You can create a new file called store or give it any desired name.

import { configureStore } from "@reduxjs/toolkit";
import User from "./slices/userSlice";

const store = configureStore({
 reducer: {
  User: User,
 },
});

export default store;

Step 2:

In the index.js file, you need to include the provider as shown below:

import React from "react";
import ReactDOM from "react-dom/client";
import App from "./App";
import { Provider } from "react-redux";
import store from "./store/index";

const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(
 <Provider store={store}>
  <App />
 </Provider>
);

Step 3:

Utilize useSelector to access the user from anywhere in this manner:

const user = useSelector((state) => state.User.user); 
console.log(user);

Answer 3

Answer №2

const getUser = (state) => state.user === null ? '' : state.user.user;
// or
const fetchUser = (state) => state.user === null ? {} : state.user.user;

Answer 4

const getUser = (state) => state.user === null ? '' : state.user.user;
// or
const fetchUser = (state) => state.user === null ? {} : state.user.user;

Answer 5

Answer №3

To optimize your code, consider declaring the initial state outside of the createSlice function:

import { createSlice } from '@reduxjs/toolkit';

const defaultUserState = { user: null }

export const userSlice = createSlice({
  name: 'user',
  initialState: defaultUserState,
  reducers: {
    login: (state, action) => {
      state.user = action.payload;
    },
    logout: (state) => {
      state.user = null;
    },
  },
  
});

export const { login, logout } = userSlice.actions;

export const selectUser = (state) => state.user.user;

export default userSlice.reducer;

Alternatively, you can simplify by directly providing an object as the initial state:

import { createSlice } from '@reduxjs/toolkit';

export const userSlice = createSlice({
  name: 'user',
  initialState: { user: null },
  reducers: {
    login: (state, action) => {
      state.user = action.payload;
    },
    logout: (state) => {
      state.user = null;
    },
  },
  
});

export const { login, logout } = userSlice.actions;

export const selectUser = (state) => state.user.user;

export default userSlice.reducer;

Answer 6

To optimize your code, consider declaring the initial state outside of the createSlice function:

import { createSlice } from '@reduxjs/toolkit';

const defaultUserState = { user: null }

export const userSlice = createSlice({
  name: 'user',
  initialState: defaultUserState,
  reducers: {
    login: (state, action) => {
      state.user = action.payload;
    },
    logout: (state) => {
      state.user = null;
    },
  },
  
});

export const { login, logout } = userSlice.actions;

export const selectUser = (state) => state.user.user;

export default userSlice.reducer;

Alternatively, you can simplify by directly providing an object as the initial state:

import { createSlice } from '@reduxjs/toolkit';

export const userSlice = createSlice({
  name: 'user',
  initialState: { user: null },
  reducers: {
    login: (state, action) => {
      state.user = action.payload;
    },
    logout: (state) => {
      state.user = null;
    },
  },
  
});

export const { login, logout } = userSlice.actions;

export const selectUser = (state) => state.user.user;

export default userSlice.reducer;

Error: Trying to access a property that is not defined (reference to 'user')

Answer №1

Answer №2

Answer №3

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