Generic Reducers/Actions in React/Redux

Question

I am trying to determine how to pull in multiple pieces of data to use in the same component.

Every example I see with React/Redux requests very specific data and has reducers and actions to handle that exact type of data. However, I have not been able to find information about handling more generic data.

For example, I have a few different components (or categories) on my site. One of those components is Cards. So, if a user clicks on the link for /cards/hockey it should request the hockey data from the API (if it isn't in the store already), and display it in the Cards page. If a user clicks the link for /cards/football, it should follow the same procedure, checking to see if it has the data in store yet, if not pulling it from the API, and displaying the Cards page with that data.

Another component type might be stats with stats about different sports teams.

I will not always know what types of cards are available ahead of time, so I cannot hardcode the specific sports types in my application.

So in this case, I'd like to only create two components: cards and stats, but have dynamically loaded data to populate those components.

Right now I have too much repetition going on and it is hard coded. This means that I cannot dynamically add new types in the future without creating new code to handle each of these types.

So, for example, right now I have /actions/footballCardActions.js and /actions/hockeyCardActions.js. I then have /reducers/footballCardReducers.js and /reducers/hockeyCardReducers.js. I might have similar components for the Stats component as well.

I'm also specifying status such as FETCH_HOCKEY_CARDS_SUCCESS or FETCH_FOOTBALL_CARDS_SUCCESS.

Again these are all hard coded, which makes scalability difficult.

One example I am trying to follow is https://scotch.io/tutorials/bookshop-with-react-redux-ii-async-requests-with-thunks - but again it uses very specific data requests, rather than generic ones.

What can I do to make my code work more generically so that I do not need to hard code specific datasets. Are there any good tutorials out there that deal with a similar situation?

More clarification

One of my components (screens) is a sports card screen. The menu system (with links) is automatically generated on site load from an API so I do not always know what links are available. So, there may be links for hockey, football, as well as a number of other sports that I have not thought of. When the menu link is clicked, it will call the API for that sport type and display the data on the sports card screen.

Based on the above link (and other similar sites) I've figured out how to hard-code each request for a specific sport in the actions and reducers section, but I have not been able to figure out how to do this generically if I do not know the sports ahead of time.

Further clarification based on current answers

If someone adds a new sport to the API database called MuffiBall, my application needs to be able to handle it. So, I cannot be expected to add new JavaScript code for each new sport that is added to the API.

All sports cards retrieved from the database follow the same structure.

An outline of my current code

index.js

//index.js
//Other imports here (not shown)
import Cards from './components/CardsPage'
import * as cardActions from './actions/cardActions';
import * as statsActions from './actions/statsActions';

import configureStore from './store/configureStore';

const store = configureStore();

/* Bad place to put these, and currently I am expected to know what every sport is*/
store.dispatch(hockeyActions.fetchHockey());
store.dispatch(footballActions.fetchFootball());
store.dispatch(muffiballActions.fetchMuffiball());


render(
  
          
                

                    /* Navigation menu here (not shown) */
                    /* Currently it is manually coded, */
                    /* but I will be automatically generating it based on API */

                      
                      
                      
                      
                
          
  ,
  document.getElementById('app')
);

store/configureStore.js

// store/configureStore.js
import {createStore, compose, applyMiddleware} from 'redux';
// Import thunk middleware
import thunk from 'redux-thunk';
import rootReducer from '../reducers';

export default function configureStore(initialState) {
  return createStore(rootReducer, initialState,
    // Apply to store
    applyMiddleware(thunk)
  );
}

actions/actionTypes

// actions/actionTypes

export const FETCH_HOCKEY_SUCCESS = 'FETCH_HOCKEY_SUCCESS';
export const FETCH_FOOTBALL_SUCCESS = 'FETCH_FOOTBALL_SUCCESS';
export const FETCH_MUFFIBALL_SUCCESS = 'FETCH_MUFFIBALL_SUCCESS';

actions/hockeyActions.js (one such file for every sport - need to make this one generic file):

// hockeyActions.js (one such file for every sport - need to make this one generic file):

import Axios from 'axios';

const apiUrl = '/api/hockey/';
// Sync Action
export const fetchHockeySuccess = (hockey) => {
  return {
    type: 'FETCH_HOCKEY_SUCCESS',
    hockey
  }
};


//Async Action
export const fetchHockey = () => {
  // Returns a dispatcher function
  // that dispatches an action at a later time
  return (dispatch) => {
    // Returns a promise
    return Axios.get(apiUrl)
      .then(response => {
        // Dispatch another action
        // to consume data

        dispatch(fetchHockeySuccess(response.data))
      })
      .catch(error => {
        console.log(error)
        throw(error);
      });
  };
};

reducers/hockeyReducers.js (one such file for every sport - need to make this one generic file)

// reducers/hockeyReducers.js (one such file for every sport - need to make this one generic file)

import * as actionTypes from '../actions/actionTypes'

export const hockeyReducer = (state = [], action) => {
  switch (action.type) {
    case actionTypes.FETCH_HOCKEY_SUCCESS:
          return action.hockey;
    default:
          return state;
  }
};

reducers/index.js

// reducers/index.js

import { combineReducers } from 'redux';
import {hockeyReducer} from './hockeyReducers'
import {footballReducer} from './footballReducers'
import {muffiballReducer} from './muffiballReducers'

export default combineReducers({
  hockey: hockeyReducer,
  football: footballReducer,
  muffiball: muffiballReducer,
  // More reducers for each sport here
});

components/CardsPage.js:

//components/CardsPage.js

import React from 'react';
import { connect } from 'react-redux';

class Cards extends React.Component{
  constructor(props){
    super(props);

    this.state = {
        data: this.props.data,
    }

  }

  componentWillReceiveProps(nextProps){
        this.setState({
                data: nextProps.data,
        })
  }

  render(){

    return(
        {/* cards displayed from this.state.data */}
    )
  }
}

const mapStateToProps = (state, ownProps) => {
  return {
    data: state[ownProps.match.params.val]
  }
};

export default connect(mapStateToProps)(Cards);

user_1315176 · Answer

take a step back and identify the data types that have unique shapes, eg cards and stats. You will build a store slice for each of these with it's own actions, reducers, and selectors. The sport should just be a variable you use as an argument to your actions and selectors. eg

Async Action

export const fetchCards = (sport) => {
  return (dispatch) => {
    return Axios.get(`/api/${sport}/`)
      .then(response =>
        dispatch(fetchCardSuccess({ sport, data: response.data }))
      )
      .catch(error => {
        console.log(error)
        throw(error);
      });
  };
};

Reducer

export const cardReducer = (state = {}, action) => {
  switch (action.type) {
    case actionTypes.FETCH_CARD_SUCCESS:
      return { ...state, [action.sport]: action.data };
    default:
      return state;
  }
};

Card Selector

export const getSport(state, sport) {
  return state.cards[sport];
}

You'll probably want another slice for managing a list of the available sports, fetched from the server, and other global data.

user_2734369 · Answer

Soo this assumes your "generic data" always will have the same shape.

You could have a generic component. Not sure how you are doing routing, but you can use the path name of the URL to determine which data to fetch and display.

The route component (React Router 4) could look like this:

Then in your component you can use react-redux to map your redux state to the component props. In componentDidMount you could see if you have the appropriate data. If you do not have the appropriate data then dispatch an action from componentDidMount to fetch it. Something like this

import { connect } from 'react-redux';
import React from 'react';
import { fetchDataAction } from './actions';

class Results extends React.Component {
  componentDidMount() {
    // check if results exists, if not then fire off an action to get 
    // data. Use whatever async redux pattern you want
    if (!this.props.results) {
      this.props.fetchData();
    }
  }

  render() { /* DO SOMETHING WITH RESULTS, OR LACK OF */ }
}

const mapStateToProps = (state, ownProps) => ({
  results: state.results[ownProps.match.params.id],
});

const mapDispatchToProps = (dispatch, ownProps) => ({
  fetchData() {
    // send path parameter via action to kick off async fetch
    dispatch(fetchDataAction(ownProps.match.params.id));
  },
});

export default connect(mapStateToProps, mapDispatchToProps)(Results);

You could have a results reducer that would just be an object that maps category to results. Here is what the results reducer could look like:

export default (state = {}, action) => {
  switch(action.type) {
    case 'FETCH_LOADED':
      const { payload: { type, results } } = action;
      return {
        ...state,
        [type]: results,
      };
    default:
      return state;
  };
};

user_10301134 · Answer

A methodology that is picking up popularity for reusable redux actions/reducers is Redux Ducks. Here's a good helper library and example to implement this in your codebase.

Building off the example in the above link that would look something like this for you:

// remoteObjDuck.js

import Duck from 'extensible-duck'
import axios from 'axios'

export default function createDuck({ namespace, store, path, initialState={} }) {
  return new Duck({
    namespace, store,

    consts: { statuses: [ 'NEW', 'LOADING', 'READY', 'SAVING', 'SAVED' ] },

    types: [
      'UPDATE',
      'FETCH', 'FETCH_PENDING',  'FETCH_FULFILLED',
      'POST',  'POST_PENDING',   'POST_FULFILLED',
    ],

    reducer: (state, action, { types, statuses, initialState }) => {
      switch(action.type) {
        case types.UPDATE:
          return { ...state, obj: { ...state.obj, ...action.payload } }
        case types.FETCH_PENDING:
          return { ...state, status: statuses.LOADING }
        case types.FETCH_FULFILLED:
          return { ...state, obj: action.payload.data, status: statuses.READY }
        case types.POST_PENDING:
        case types.PATCH_PENDING:
          return { ...state, status: statuses.SAVING }
        case types.POST_FULFILLED:
        case types.PATCH_FULFILLED:
          return { ...state, status: statuses.SAVED }
        default:
          return state
      }
    },

    creators: ({ types }) => ({
      update: (fields) => ({ type: types.UPDATE, payload: fields }),
      get:        (id) => ({ type: types.FETCH, payload: axios.get(`${path}/${id}`),
      post:         () => ({ type: types.POST, payload: axios.post(path, obj) }),
      patch:        () => ({ type: types.PATCH, payload: axios.patch(`${path}/${id}`, obj) })
    }),

    initialState: ({ statuses }) => ({ obj: initialState || {}, status: statuses.NEW, entities: [] })
  })
}

and each sport would create a single duck that will reuse the same functionality.

Hockey:

// hockeyDuck.js

import createDuck from './remoteObjDuck'

export default createDuck({ namespace: 'my-app', store: 'hockeyCards', path: '/cards/hockey' })

Football:

// footballDuck.js

    import createDuck from './remoteObjDuck'

    export default createDuck({ namespace: 'my-app', store: 'footballCards', path: '/cards/football' })

Then combine the reducers in the store:

// reducers.js

import { combineReducers } from 'redux'
import footballDuck from './footballDuck'
import hockeyDuck from './hockeyDuck'

export default combineReducers({ [footballDuck.store]: footballDuck.reducer, [hockeyDuck.store]: hockeyDuck.reducer })

If you want to dynamically add reducers to redux on the fly you will have to use something like: https://github.com/ioof-holdings/redux-dynamic-reducer. Then you can create the duck on the fly depending on your API call response:

//get from API
var sport = "football";
var footballDuck = createDuck({ namespace: 'my-app', store: 'cards', path: `/cards/${sport}` });
store.attachReducer({ [footballDuck.store]: footballDuck.reducer });

user_10333103 · Answer

// structure (something like...)

/*
./components 
./redux
./redux/actions
./redux/reducers
./redux/sagas
./redux/types
./util
*/
 
/* ------------------------------------------------- */

/* package.json */

{
  (...)
  "proxy": "http://localhost:3000",
  (...)  
}
 
/* ------------------------------------------------- */

/* index.js or otherComponent.js */

import React from 'react' 
import { render } from 'react-dom'
import { createStore, applyMiddleware } from 'redux'
import { Provider } from 'react-redux'
import reducers from './redux/reducers/index'
import logger from 'redux-logger'
import createSagaMiddleware from 'redux-saga'
import indexSagas from './redux/sagas/indexSagas'

import { environment } from './util/baseUrl'

const sagaMiddleware = createSagaMiddleware()

const store = 
  environment === 'DEV' ?
    createStore(
      reducers,
      window.__REDUX_DEVTOOLS_EXTENSION__ && 
      window.__REDUX_DEVTOOLS_EXTENSION__(),  
      applyMiddleware(sagaMiddleware, logger)
    ) :
    createStore(
      reducers,
      applyMiddleware(sagaMiddleware)
    ) 

sagaMiddleware.run(indexSagas)

render(
   
            
   ,
 document.getElementById('app'))
 

/* ------------------------------------------------- */

/* baseURL.js */

const DEV = 'DEV'
const PROD = 'PROD'

/*-----------------------------------------*/
/*------*/ export const environment = DEV /* <------- */
/*-----------------------------------------*/

export const baseURL = 
    environment === DEV ?
    '/api/v1/' : 
    'https://abcde.website.net/api/v1/' 
 
/* ------------------------------------------------- */

/* genericTypes.js */

export const GET_REGISTERS_REQUEST = 'GET_REGISTERS_REQUEST'
export const GET_REGISTERS_SUCCESS = 'GET_REGISTERS_SUCCESS'
export const GENERIC_ERROR_MSG = 'GENERIC_ERROR_MSG'

/* ------------------------------------------------- */

/* actions.js */

export const getRegistersRequest = ( route ) => {
  return {
    type: GET_REGISTERS_REQUEST,
    route,
  }
}
export const getRegistersSuccess = ( data ) => {
  return {
    type: GET_REGISTERS_SUCCESS,
    data,
  }
} 
export const genericErrorMsg = ( errorMsg ) => {
  return {
    type: GENERIC_ERROR_MSG,
    errorMsg,
  }
}

/* ------------------------------------------------- */

/* genericReducer.js */

import { GET_REGISTERS_REQUEST, GET_REGISTERS_SUCCESS, GENERIC_ERROR_MSG } from '../types/genericTypes'

const INITIAL_STATE = {
  data: [],
  isFetching: false,
  isLoaded: false,
  error: false,
  errorMsg: '',
}

const genericReducer = (state = INITIAL_STATE, action) => {
  switch(action.type){
    case GET_REGISTERS_REQUEST:
      return {
        ...state,
        data: [],
        isFetching: true,
        isLoaded: false,
        error: false,
        errorMsg: '',
      }  
    case GET_REGISTERS_SUCCESS:
      return {
        ...state,
        data: action.data,
        isFetching: false,
        isLoaded: true,
      }
    case GENERIC_ERROR_MSG: 
      return {
        ...state,
        isFetching: false,
        error: true,
        errorMsg: action.errorMsg,
      }   
    default:
      return state
  }
}
export default genericReducer  

/* ------------------------------------------------- */

/* yourComponent.js  */

import React, { Component } from "react"
import { connect } from 'react-redux'
import { getRegistersRequest } from '../../redux/actions'   

//(...)
// this.props.getRegistersRequest('cards/hockey')
// this.props.getRegistersRequest('cards/football')
//(...)

const mapStateToProps = (state) => {
  return {
    data: state.genericReducer.data,
    isFetching: state.genericReducer.isFetching,
    isLoaded: state.genericReducer.isLoaded,
    error: state.genericReducer.error,
    errorMsg: state.genericReducer.errorMsg,
  } 
}
const mapDispatchToProps = (dispatch) => {
  return {
    getRegistersRequest: ( route ) => dispatch(getRegistersRequest( route )),
  }
}
export default connect(mapStateToProps, mapDispatchToProps)(yourComponent)

/* ------------------------------------------------- */

/* indexSagas.js */

import { takeLatest } from 'redux-saga/effects'
import axios from 'axios'

import { GET_REGISTERS_REQUEST } from '../types/genericTypes'
import { getRegistersRequest } from './genericSagas'

function* indexSagas() {
  try {
    yield (takeLatest(GET_REGISTERS_REQUEST, getRegistersRequest, axios))  
  }
  catch (e) {
    // (...)
  }
}
export default indexSagas  

/* ------------------------------------------------- */

/* genericSagas.js */

import { put } from 'redux-saga/effects'

import { getRegistersSuccess, genericErrorMsg } from '../actions'

export function* getRegistrosRequest(axios, action) {
  const rest = createRest(axios)
  try {
    let route = ''
    switch (action.route) {
      case 'cards/hockey':
      case 'cards/football':
        route = action.route
        break
      default: {
        yield put(genericErrorMsg('Route [ ' + action.route + ' ] not implemented yet!'))
        return
      }
    }    
    const data = yield rest.get(route)
    yield put(getRegistersSuccess(data))
  }
  catch (e) {
    yield put(genericErrorMsg(e))
  }
}

/* ------------------------------------------------- */

/* createRest */

import { baseURL } from '../../util/baseUrl'
function createRest(axios){
  const token = localStorage.getItem('yourToken')
  const rest = axios.create({
    baseURL: baseURL,
    headers:{
      Authorization: 'Bearer ' + token
    }
  })
  return rest  
}
export default createRest
 
/* ------------------------------------------------- */

Generic Reducers/Actions in React/Redux

4 Answers