JSFiddle - React, Tailwind, and code Playground

JavaScript

function setCookie(name, value, days) {
  var d = new Date;
  d.setTime(d.getTime() + 24 * 60 * 60 * 1000 * days);
  document.cookie = name + "=" + value + ";path=/;expires=" + d.toGMTString();
}

function getCookie(name) {
  var v = document.cookie.match('(^|;) ?' + name + '=([^;]*)(;|$)');
  return v ? v[2] : null;
}

function getUser() {
  let user = getCookie('ds_user')
  if (!user) {
    return null
  }
  return JSON.parse(atob(user))
}


const mockUser = {
  user: {
    id: "1671",
    email: "[email protected]",
    username: "art",
    firstName: "Art",
    lastName: "Vandalay",
    phone: null,
    admin: true,
    title: "",
    guid: "u0000ZDCF4",
    vendorUser: false,
    lastLogin: "2019-06-07 18:52:11",
    defaultStoreId: "6",
  },
  store: {
    storeId: 6,
    name: "Demo Store",
    marketId: 13
  }
}

setCookie('ds_user', btoa(JSON.stringify(mockUser)), 7)

console.log( getUser() )