1. 크롬 웹스토어에서 REDUX DEVTOOLS 다운로드하고 2. createStore마지막 인자로 ,(콤마) 하고 +부분 넣어주면 됨. const store = createStore( reducer, /* preloadedState, */ + window.__REDUX_DEVTOOLS_EXTENSION__ && window.__REDUX_DEVTOOLS_EXTENSION__() ); https://github.com/zalmoxisus/redux-devtools-extension#installation zalmoxisus/redux-devtools-extension Redux DevTools extension. Contribute to zalmoxisus/redux-devtools-extension ..