Get cookie with react

Question

I need to know if my user is connected or not. For that I want to read the cookies that I set in the server side with express-session :

app.use(session({
    secret: 'crypted key',
    resave: false,
    saveUninitialized: true,
    cookie: { secure: false } // Put true if https
}))

app.post('/connect_user', (req, res) => {
    req.session.cookie.username = req.body.username
    findUserData('username', req.body.username, req, (userData) => {
        req.session.cookie.id = userData.id
        req.session.cookie.username = userData.username
        res.redirect('/profil')
    })
})

I tried to use react-cookie but it doesn't work even though I copy-pasted the npm react-cookie docs example:

import React from 'react';
import Landing from './Landing';
import Home from './Home';
import Profil from './Profil';
import { BrowserRouter as Router, Route } from 'react-router-dom';
import { instanceOf } from 'prop-types';
import { Cookies } from 'react-cookie';

class App extends React.Component {
    static propTypes = {
        cookies: instanceOf(Cookies).isRequired
      };
     
      constructor(props) {
        super(props);
     
        const { cookies } = props;
        this.state = {
          username: cookies.get('username')
        };
      }
    render() {
        console.log(this.state.name) 
        let homePage = (!this.state.username) ? <Landing/> : <Home/>
        return (
            <Router>
                <div>
                    <Route exact path='/' component={homePage}></Route>
                    <Route path='/profil' component={Profil}></Route>
                </div>
            </Router>
        )
    }
}

export default App;

It's weird because document.cookie renders the correct result, but I don't know how handle it:

PHPSESSID=0nv9ic8h7pv2b63lu4v7eg3mop; user_id=21; username=Ugo; SL_G_WPT_TO=fr; SL_GWPT_Show_Hide_tmp=undefined; SL_wptGlobTipTmp=undefined

Answer 1

You can use js-cookie package and can install it using npm install js-cookie --save command.

import React from 'react';
import Cookies from 'js-cookie';

class App extends React.Component {
     this.state = {
        username: Cookies.get('username')
     }

//  more code....
}  

Documentation : https://github.com/js-cookie/js-cookie

NPM : https://www.npmjs.com/package/js-cookie

Answer 2

There is no need for a third party npm package. You can use plain JS to extract the cookie. Here is a custom function for that:

function getCookie(key) {
  var b = document.cookie.match("(^|;)\\s*" + key + "\\s*=\\s*([^;]+)");
  return b ? b.pop() : "";
}

Answer 3

If all you want is to get the cookie value by key, I would suggest using plain javascript without any dependencies.

In this example, it gets the cookie value by the key "username" with the help of Regex.

let cookieValue = document.cookie.replace(/(?:(?:^|.*;\s*)username\s*\=\s*([^;]*).*$)|^.*$/, "$1");

https://developer.mozilla.org/en-US/docs/Web/API/document/cookie#Example_2_Get_a_sample_cookie_named_test2

Answer 4

I'd recommend using universal-cookie as its simpler to use. Mind you, cookies have nothing to do with React. They are stored on the browser and you could use the browser's default API to get cookies.

Here is an example how you can use universal-cookies

import React from 'react';
// other imports...
import Cookies from 'universal-cookie';

const cookies = new Cookies();

class App extends React.Component {
     this.state = {
        username: cookies.get('username')
     }

//  more code....   

Source: https://www.npmjs.com/package/universal-cookie

Answer 5

You can also use the method below without any 3rd party package as documented in developer.mozilla.org :

const cookieValue = document.cookie
  .split('; ')
  .find((row) => row.startsWith('YOUR-COOKIE='))?
  .split('=')[1];

Answer 6

If you have a cookie with "httpOnly:true" property, you can't access it with document.cookie. It might be the reason you have failed to access the cookie with these methods.

Answer 7

I hope this function may help:

function getCookie(name) {
  if (document.cookie && document.cookie !== '') {
    var cookies = document.cookie.split(';');
    for (var i = 0; i < cookies.length; i++) {
      var cookie = cookies[i].trim();
      if (cookie.substring(0, name.length + 1) === (name + '=')) {
        cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
        break;
      }
    }
  }
  return cookieValue;
}

Answer 8

cookie = key=>((new RegExp((key || '=')+'=(.*?); ','gm')).exec(document.cookie+'; ') ||['',null])[1]
console.log(cookie('test'))