Redux Devtool (chrome extension) not displaying state

Did you add this line to your store?

window.__REDUX_DEVTOOLS_EXTENSION__ && window.__REDUX_DEVTOOLS_EXTENSION__()

github.com/zalmoxisus/redux-devtools-extension#11-basic-stor‌​e

I was looking at how I did it years ago and this would do the trick:

const store = createStore(reducers, 
  window.devToolsExtension && window.devToolsExtension()
)

For potential redux newcomers working on older projects/tutorials know that

window.devToolsExtensionis deprecated in favor ofwindow.REDUX_DEVTOOLS_EXTENSION`, and will be removed in next version of Redux DevTools: https://git.io/fpEJZ

as previously answered, replace with window.__REDUX_DEVTOOLS_EXTENSION__ && window.__REDUX_DEVTOOLS_EXTENSION__()

Try the following if you have setup the store using a middleware

import { createStore, applyMiddleware, compose } from 'redux';

const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;
const store = createStore(reducer, /* preloadedState, */ composeEnhancers(
    applyMiddleware(...middleware)
  ));