Category: Tech Notes

This is my summary of the bare minimum steps as a quick-ref cheatsheet for adding Redux to an existing React app. This is just some notes for future reference. If you’re looking for tutorials, take a look at:

• https://redux.js.org/introduction/getting-started
• https://react-redux.js.org/introduction/quick-start

Here’s my quickref:

npm install --save react-redux

Add Redux devtools for Chrome (see here):

npm install --save-dev redux-devtools-extension

Wrap <Provider> around root Component to share the Store with all child components:

import { Provider } from 'react-redux'
import store from './store'

<Provider store={store}>
  <App>
</Provider>

Implement mapStateToProps and mapDispatchToProps to pass store and dispatch() as props to each Component, and call connect() to connect each Component with your Redux Store:

const mapStateToProps = (state) => {
  return {
    yourcomponent: state.yourcomponent
  }
}
export default connect(
  mapStateToProps,
  mapDispatchToProps
)(YourComponent)

Create a Store:

import { createStore } from 'redux';
import { devToolsEnhancer } from 'redux-devtools-extension';
let store = createStore(yourReducer, devToolsEnhancer());
export default store;

Create reducers for Store – here’s an example that take the the value of a label from the passed action payload and sets it in the Store – remember the state of the store is always treated as immutable, so always create a new copy of the modified state, here using Object.assign():

function labelReducer(state = initialState, action) {
  switch (action.type) {
    case 'CHANGE_LABEL':
      return Object.assign( {},{ labelValue : action.payload 
    } );
    default:
      return state;
    }
}

Implement an action creator that builds an Action object that requests changes to the Store – each action has a type and a payload:

export function changeLabel(payload) {
  return { type: "LABLE_CHANGE", payload }
};

Implement mapDispatchToProps – you can either build the Action object yourself here, or call an Action creator like the above example:

function mapDispatchToProps(dispatch) {
return {
  changeLabel: labelValue => 
    dispatch(changeLabel(labelValue))
  };
}

Pass mapDispatchToProps to your connect() call shown earlier.

As a comparison, here’s a simple React app using Flux:

https://github.com/kevinhooke/SimpleReactFluxExample

… and here’s the same app converted to use Redux:

https://github.com/kevinhooke/SimpleReactReduxExample

Done!