redux-saga is not able to get payload value from dispatched action - react-redux

I am trying to create a search functionality.
So the values from the search input is actually getting passed in my actions and I can see the values from redux logger. However redux saga seems not able to intercept the payload value from the action creator. When I console log it it prints undefined.
Actions
//ACTIONS
import SearchActionTypes from "./search.types";
export const SearchActionStart = (value) => ({
type: SearchActionTypes.SEARCH_START,
value
});
export const SearchActionSuccess = (items) => ({
type: SearchActionTypes.SEARCH_SUCCESS,
payload: items,
});
export const SearchActionFailure = (e) => ({
type: SearchActionTypes.SEARCH_FAILURE,
payload: e,
});
Search Component
import React, { useEffect, useState } from "react";
import { connect } from "react-redux";
import { createStructuredSelector } from "reselect";
import { selectFieldData } from "../../redux/search/search.selector";
import { SearchActionStart } from "../../redux/search/search.actions";
const SearchComponent = (props) => {
const { searchResults, value } = props;
useEffect(() => {}, []);
const onSearchChange = (event) => {
const { value } = event.target;
searchResults(value);
};
return (
<div>
<input
type="text"
value={value}
onChange={onSearchChange}
/>
</div>
);
};
const mapDispatchToProps = (dispatch) => ({
searchResults: (value) =>
dispatch(SearchActionStart(value)),
});
const mapStateToProps = createStructuredSelector({
searchItem: selectFieldData,
});
export default connect(
mapStateToProps,
mapDispatchToProps
)(SearchComponent);
searchSaga
import {
put,
call,
takeLatest,
all,
} from "redux-saga/effects";
import { SearchImage } from "../../api/search-image";
import Axios from "axios";
import {
SearchActionStart,
SearchActionSuccess,
SearchActionFailure,
} from "./search.actions";
import SearchActionTypes from "./search.types";
function* fetchFieldAsync(value) {
try {
// const images = yield call(SearchImage, value);
console.log(value);
// yield put(SearchActionSuccess(value));
} catch (e) {
yield put(SearchActionFailure(e));
console.log(e);
}
}
export function* fetchFieldStart() {
yield takeLatest(
SearchActionTypes.SEARCH_START,
fetchFieldAsync
);
}
export function* searchFieldSaga() {
yield all([call(fetchFieldAsync)]);
}
rootSaga
import { call, all } from "redux-saga/effects";
import { searchFieldSaga } from "./search/search.saga";
export default function* rootSaga() {
yield all([call(searchFieldSaga)]);
}

Please have a look into this code sandbox(https://codesandbox.io/s/basic-redux-saga-49xyd?file=/index.js) ... Your code is working fine. In saga function you will get the object that has been sent from the action as the param. You can destructure it into {value} to get the search term alone as param instead of action object.

A very silly mistake.
In my searchSaga instead of exporting the watcher function fetchFieldStart function. I mistakenly exported the intermediary functions instead, which is the fetchFieldAsync function whose job is to fetch an API.
So in
searchSaga.js
instead of:
export function* searchFieldSaga() {
yield all([call(fetchFieldAsync)]);
}
It should be:
export function* searchFieldSaga() {
yield all([call(fetchFieldStart)]);
}
For anyone who might encounter undefined error in your sagas, it might be worth reviewing if your exporting correct functions.
I hope this could also help anyone who have encountered similar problem
Thanks evryone.

Related

How to display fetched data in functional react-redux component?

Why I see always "loading..."?
I used redux-toolkit and createSlice and fetch data by axios.
I have not any problem by fetching data and my data is in State.
My problem is displaying fetched data.
My Component code is:
import React, {useEffect, useState} from 'react';
import { useDispatch, useSelector } from 'react-redux';
import {fetchTrackers} from 'dashboard/dashboardSlice';
export default function TrackerManagerDashboard() {
const [trackersList, setTrackersList] = useState(useSelector(state => state.trackersData));
const [activeTracker, setActiveTracker] = useState(useSelector(state => state.activeTracker));
const dispatch = useDispatch();
useEffect(() => {
dispatch(fetchTrackers);
}, []);
if(!trackersList)
return (
<div>loading...</div>
)
return (
<div className="TrackerManagerDashboard">
...
</div>
)
}
and reducer Slice file is:
import { createSlice } from '#reduxjs/toolkit'
import * as env from "../../environments";
import axios from 'axios';
const initialState = {
trackersData: {},
activeTracker: {},
}
const dashboardSlice = createSlice({
name: 'dashboard',
initialState,
reducers: {
setInitialState(state, action) {
state.trackersData = action.payload.data;
state.activeTracker = state.trackersData[Object.keys(state.trackersData)[0]];
},
},
})
export async function fetchTrackers (dispatch, getState) {
try {
const { data } = await axios.get(env.APP_URL + '/fetch/trackers.json');
dispatch(setInitialState({type: 'setInitialState', data }));
} catch(error) {
console.log(error);
}
}
export const { setInitialState} = dashboardSlice.actions
export default dashboardSlice.reducer
Never use useState(useSelector.
That means "create a component-local state with the initial value that the return value of useSelector at the time of first render has". If the Redux state changes later, you will never get to see it, as your useState is already initialized and any change there will not be reflected in your trackersList variable.
Instead, just call useSelector:
const trackersList = useSelector(state => state.trackersData);
const setActiveTracker = useSelector(state => state.activeTracker);

[updated]Intergrating NextJS and Redux State Management

this my updated version of intergrating redux and NextJS. Just to elobarate what I have done so far...
STEP 1. I've created a store.js file to set up my global store in reference to github's explanation from nextJS developers.
import { createStore, applyMiddleware, combineReducers } from 'redux';
import { createWrapper, HYDRATE } from 'next-redux-wrapper';
import thunkMiddleware from 'redux-thunk';
import { customerListReducer } from './customerReducers';
const bindMiddleware = (middleware) => {
if (process.env.NODE_ENV !== 'production') {
const { composeWithDevTools } = require('redux-devtools-extension');
return composeWithDevTools(applyMiddleware(...middleware));
}
return applyMiddleware(...middleware);
};
const combinedReducer = combineReducers({
customerList: customerListReducer,
});
const reducer = (state, action) => {
console.log('Just Displaying the Store', state);
if (action.type === HYDRATE) {
const nextState = {
...state, // use previous state
...action.payload, // apply delta from hydration
};
if (state.count) nextState.count = state.count; // preserve count value on client side navigation
return nextState;
} else {
return combinedReducer(state, action);
}
};
// create a makeStore function
const store = () =>
createStore(
reducer,
bindMiddleware([thunkMiddleware])
);
// export an assembled wrapper
export const wrapper = createWrapper(store);
STEP 2: Imported the wrapper above in my _app file to make the wrapper available across all pages in my application
import Nav from '../components/Nav';
import {wrapper} from '../reducers/store';
function MyApp({ Component, pageProps }) {
return (
<>
<Nav />
<Component {...pageProps} />
</>
);
}
export default wrapper.withRedux(MyApp);
STEP 3: CONFIGURATIONS
A) My Action that calls external API
import axios from 'axios';
import {
CUSTOMER_LIST_REQUEST,
CUSTOMER_LIST_SUCCESS,
CUSTOMER_LIST_FAIL,
} from '../constants/customerConstants';
export const listCustomers = () => async (dispatch) => {
try {
dispatch({
type: CUSTOMER_LIST_REQUEST,
});
const { data } = await axios.get(
'https://byronochara.tech/gassystem/api/v1/customers'
);
const result = data.results;
dispatch({
type: CUSTOMER_LIST_SUCCESS,
payload: result,
});
} catch (error) {
dispatch({
type: CUSTOMER_LIST_FAIL,
payload:
error.response && error.response.data.message
? error.response.data.message
: error.message,
});
}
};
B)My Action Reducer
import {
CUSTOMER_LIST_REQUEST,
CUSTOMER_LIST_SUCCESS,
CUSTOMER_LIST_FAIL,
} from '../constants/customerConstants';
import { HYDRATE } from 'next-redux-wrapper';
export const customerListReducer = (state = { customers: [] }, action) => {
switch (action.type) {
case HYDRATE:
return { loading: true, customers: [] };
case CUSTOMER_LIST_REQUEST:
return { loading: true, customers: [] };
case CUSTOMER_LIST_SUCCESS:
return {
loading: false,
customers: action.payload,
};
case CUSTOMER_LIST_FAIL:
return { loading: false, error: action.payload };
default:
return state;
}
};
C)The finally bringing it all together in my index.js page to display the results:
import React, { useEffect } from 'react';
import Head from 'next/head';
import { useSelector} from 'react-redux';
import { listCustomers } from './../actions/customerActions';
import { wrapper } from '../reducers/store';
import styles from '../styles/Home.module.css';
const Home = () => {
//Select the loaded customers' list from central state
const customerList = useSelector((state) => {
console.log(state);
return state.customerList;
});
const { loading, error, customers } = customerList;
//displaying the customers data from the external API
console.log('Fetched Customers Data', customers);
return (
<div className={styles.container}>
<Head>
<title>Home | Next</title>
</Head>
<h1>Welcome to Home Page</h1>
{/* {loading && <h6>Loading...</h6>} */}
{/* {error && <h6>Error Occured...</h6>} */}
{/* {customers.map((customer) => (
<h3>{customer.customerName}</h3>
))} */}
{/* <ArticleList customers={customers} /> */}
</div>
);
};
// getStaticProp at build time
// getServerSideProp at every request slower
// getStaticPath to dynamically generate paths based on the data we are fetching
export const getStaticProps = wrapper.getServerSideProps(async ({ store }) => {
// console.log('STORE', store);
store.dispatch(listCustomers());
});
export default Home;
COMMENT ON THE PROBLEM I'M FACING FROM THE ABOVE CODE: once everything has been set up if you follow the code above, the code seems to run well the store is successfully created when I log the result on the console ``{ customerList: { loading: true, customers: [] } }. But then I guess this is the result from the HYDRATE action type since it will always be dispatch since am using getStaticProps``` that creates a new store instance in the server.
MAIN QUIZ: My challenge is how do I bypass the HYDRATED action and reconcile the server side state with the client side store and persist it and at least to finally be able to view the list from the external API. Thanks in advance. :)
I totally recommend you to use reduxjs/toolkit. It's very simple , less code, no wrappers, clean. And no matter your project on nextjs or created via CRA. Also you dont need to configure redux-thunk and redux-devtools cause they are enabled by default. Read documentation for more information ( how to persist state without any npm package and so on )
Here is a little example.
store.js
import { combineReducers, configureStore } from "#reduxjs/toolkit";
import userSlice from './user.slice.js';
//reducers
const rootReducer = combineReducers({
user: userSlice
});
const store = configureStore({
reducer: rootReducer,
});
export default store;
Wrap with Provider (in your case _app.js)
<Provider store={store}>
<Component {...pageProps} />
</Provider>
user.slice.js ( action + reducer )
import { createSlice, createAsyncThunk } from '#reduxjs/toolkit';
const initialState = {
id: '',
email: '',
roles: []
};
// export async action
export const signIn = createAsyncThunk('user/signIn', async (data) => {
try {
const payload = await api.auth.signin(data).then((res) => res.data);
// do some stuff if you want
return payload ;
} catch (err) {
console.log(err.response);
}
});
const userSlice = createSlice({
name: 'user',
initialState,
reducers: {
removeUser(state, payload) {
//cant be an async method
return initialState;
},
extraReducers: (builder) => {
builder.addCase(signIn.fulfilled, (state, { payload }) => {
// payload from the async method above (asyncThunk)
return payload;
});
},
},
});
// export actions
export const { removeUser } = userSlice.actions;
// export reducer
export default userSlice.reducer;
Thats it. Last step to call actions from any component e.g.
import { useDispatch, useSelector } from 'react-redux';
import { signIn, removeUser } from '../actions/userSlice';
// in function component
// call hooks
const dispatch = useDispatch();
// read the store
const { user } = useSelector((state) => state);
// dispatch any action , example below
dispatch(signIn(userCredentials));
// or
dispatch(removeUser());
I has an Issue with setting Redux with NextJS and this is my final answer after some insight from mirik999 too.
A. my store.
import { configureStore } from '#reduxjs/toolkit';
//importing the slice file with sliced reducers
import customerListReducer from '../slices/customerSlice';
// const composedEnhancer = composeWithDevTools(applyMiddleware(thunkMiddleware));
const store = configureStore({
reducer: {
customerList: customerListReducer,
},
});
export default store;
B. The store is provided in my app component
function MyApp({ Component, pageProps }) {
return (
<Provider store={store}>
<Nav />
<Component {...pageProps} />
</Provider>
);
}
export default MyApp;
C. The Slice file that automatically creates action creators and the reducer
import { createSlice } from '#reduxjs/toolkit';
//creating and action that calls API from a REST API backend
export const customersFetchedList = createAsyncThunk(
'customersList/customersListSuccess',
async () => {
try {
const { data } = await axios.get(
'https://example.com/api/your/endpoint'
);
const result = data.results;
//the payload
const payload = result;
return payload;
} catch (error) {
console.log(error.response);
const payload =
error.response && error.response.data.message
? error.response.data.message
: error.message;
return payload;
}
}
);
const initialState = {
loading: true,
customers: [],
error: false,
};
const customerListSlice = createSlice({
name: 'customersList',
initialState,
reducers: {
//reducer functions we've provided
customersRequest(state, action) {
if (state.loading == true) {
return state;
}
},
},
extraReducers: (builder) => {
initialState,
builder.addCase(customersFetchedList.fulfilled, (state, action) => {
state.loading = false;
state.customers = action.payload;
state.error = false;
return state;
});
},
});
export const {
customersRequest,
customersLoadingError,
} = customerListSlice.actions;
export default customerListSlice.reducer;
D. Then finally fired this action above in my component using the useEffect()
import React, { useEffect } from 'react';
import Head from 'next/head';
const Home = () => {
//method to fire the action
const dispatch = useDispatch();
//Select the loaded customers' list from central state
const customerList = useSelector((state) => state);
// const { loading, error, customers } = customerList;
useEffect(() => {
dispatch(listCustomers());
}, []);
return (
<div className={styles.container}>
<Head>
<title>Home | Next</title>
</Head>
<h1>Welcome to Home Page</h1>
{loading && <h6>Loading...</h6>}
{error && <h6>Error Occured...</h6>}
{customers.map((customer) => (
<h3>{customer.customerName}</h3>
))}
</div>
);
};
Thanks so much for your contribution. :)

Load data before createStore

I’ve created some React files where one initializes a Redux store. However, I really need to load some data from a json file before store is initialized.
I’ve tried to import a script loading the json structure then assigning it to the createStore initialState value. But createStore runs before the data is loaded and assigned.
Is there any simple way to say “dont do anything before my axios call is done”???
Action types
actiontypes.js
export const LOAD_DATA_REQUEST='LOAD_DATA_REQUEST';
export const LOAD_DATA_SUCCESS='LOAD_DATA_SUCCESS';
export const LOAD_DATA_ERROR='LOAD_DATA_ERROR';
Actions
actions.js
import * as Actions from './actiontypes';
function load() {
return { type: Actions.LOAD_DATA_REQUEST };
}
function success(res) {
return { type: Actions.LOAD_DATA_SUCCESS, payload: res };
}
function error(ex) {
return { type: Actions.LOAD_DATA_ERROR, payload: ex };
}
export function loadData(url) {
return (dispatch) => {
dispatch(load());
axios.get(url).then((res) => {
dispatch(success(res));
}).catch((ex) => {
dispatch(error(ex));
});
};
}
use this in reducers that requires
import * as Actions from './actiontypes';
const newState = Object.assign({}, state);
switch (action.type) {
case Actions.LOAD_DATA_REQUEST:
{
//maybe you load
newState.loading = true;
return newState;
}
case Actions.LOAD_DATA_SUCCESS:
{
const res = action.payload;
//do what you need for this reducer
return newState;
}
case Actions.LOAD_DATA_ERROR:{
/// maybe you will want to show some error message in some reducer?
return newState;
}
}
You just need the first screen of your application on componentWillMount() call the loadData() action
I hope this can help you

react-redux initial ajax data and generate childrens

I am new to react-redux.I have to says I read a lot of example project, many use webpack and couple a lot of package together without detailed introduction. I also read official example several times, but I still can not understand it well, specially in how to get initial data, and show it in the dom and communicate with ajax(not like jquery.ajax, use ajax in redux seems very complex, everyone's code has different approach and different style make it much hard to understand)
I decide to build a file manager webui to learn react-redux.
To begin, I just want it work, so no ajax:
containers/App.js:
import React, { Component, PropTypes } from 'react';
import { bindActionCreators } from 'redux';
import { connect } from 'react-redux';
import {getFileList} from '../actions/NodeActions'
import Footer from '../components/Footer';
import TreeNode from '../containers/TreeNode';
import Home from '../containers/Home';
export default class App extends Component {
componentDidMount() {
let nodes = getFileList();
this.setState({
nodes: nodes
});
}
render() {
const { actions } = this.props;
const { nodes } = this.state;
return (
<div className="main-app-container">
<Home />
<div className="main-app-nav">Simple Redux Boilerplate</div>
{nodes.map(node =>
<TreeNode key={node.name} node={node} {...actions} />
)}
<Footer />
</div>
);
}
}
function mapStateToProps(state) {
return {
test: state.test
};
}
function mapDispatchToProps(dispatch) {
return {
actions: bindActionCreators(getFileList, dispatch)
};
}
export default connect(
mapStateToProps,
mapDispatchToProps
)(App);
actions/NodeActions.js:
import { OPEN_NODE, CLOSE_NODE } from '../constants/ActionTypes';
export function openNode() {
return {
type: OPEN_NODE
};
}
export function closeNode() {
return {
type: CLOSE_NODE
};
}
class NodeModel {
constructor(name, path, type, right) {
this.name = name;
this.path = path;
this.type = type;
this.right = right;
}
}
const testNodes = [
new NodeModel('t1','t1', 'd', '777'),
new NodeModel('t2','t2', 'd', '447'),
new NodeModel('t3','t3', 'd', '667'),
]
export function getFileList() {
return {
nodes: testNodes
}
}
export function ansyncGetFileList() {
return dispatch => {
setTimeout(() => {
dispatch(getFileList());
}, 1000);
};
}
reducers/index.js
import { combineReducers } from 'redux';
import opener from './TreeNodeReducer'
const rootReducer = combineReducers({
opener
});
export default rootReducer;
reducers/TreeNodeReducer.js
import { OPEN_NODE, CLOSE_NODE } from '../constants/ActionTypes';
const initialState = [
{
open: false
}
]
export default function opener(state = initialState, action) {
switch (action.type) {
case OPEN_NODE:
return true;
case CLOSE_NODE:
return false;
default:
return state;
}
}
reducers/index.js
import { combineReducers } from 'redux';
import opener from './TreeNodeReducer'
const rootReducer = combineReducers({
opener
});
export default rootReducer;
store/store.js(a copy from a redux demo):
import { createStore, applyMiddleware, compose } from 'redux';
import rootReducer from '../reducers';
import createLogger from 'redux-logger';
import thunk from 'redux-thunk';
import DevTools from '../containers/DevTools';
const logger = createLogger();
const finalCreateStore = compose(
// Middleware you want to use in development:
applyMiddleware(logger, thunk),
// Required! Enable Redux DevTools with the monitors you chose
DevTools.instrument()
)(createStore);
module.exports = function configureStore(initialState) {
const store = finalCreateStore(rootReducer, initialState);
// Hot reload reducers (requires Webpack or Browserify HMR to be enabled)
if (module.hot) {
module.hot.accept('../reducers', () =>
store.replaceReducer(require('../reducers'))
);
}
return store;
};
chrome console says:Uncaught TypeError: Cannot read property 'nodes' of null at App render() {
I don't know the es6 well, due to react-redux strange syntax make me read the es6 doc, but I am not sure my code is right.
Tring:
I think maybe can not create testNodes with new instance in the list, so I change testNodes to plain json:
const testNodes = [
{name:'t1',type:'t1'},
{name:'t2',type:'t2'},
{name:'t3',type:'t3'},
]
Still same error
maybe action can not get the global testNodes? I move testNodes into getFileList, not work too.
I have no idea.
After solve this, I would try to replace getFileList content to a ajax call.
PS:My react-route also have strange problem, chrome show blank page and no error when I wrap App with route, just feel react-redux is so hard for newbee...this is just some complain...
Simply
you don't need to bindActionCreators yourself
you need to use this.props.getFileList
you don't need to manage it with component's state
for eg.
import {ansyncGetFileList} from '../actions/NodeActions'
componentWillMount() {
// this will update the nodes on state
this.props.getFileList();
}
render() {
// will be re-rendered once store updated
const {nodes} = this.props;
// use nodes
}
function mapStateToProps(state) {
return {
nodes: state.nodes
};
}
export default connect(
mapStateToProps,
{ getFileList: ansyncGetFileList }
)(App);
Great Example
Update based on the question update and comment
since your state tree doesn't have a map for nodes you'll need to have it in the state's root or opener sub tree.
for async operation you'll have to modify your thunk action creator
for eg.
export function ansyncGetFileList() {
return dispatch => {
setTimeout(() => {
dispatch({ type: 'NODES_SUCCESS', nodes: getFileList()}); // might need to export the type as constant
}, 1000);
};
}
handle the NODES_SUCCESS action type in reducer
const initialState = {
nodes: []
};
export default function nodes(state = initialState, action) {
switch (action.type) {
// ...
case 'NODES_SUCCESS':
let nodes = state.nodes.slice();
return nodes.concat(action.nodes);
// ...
}
}
use nodes reducer to manage nodes sub tree
for eg.
import { combineReducers } from 'redux';
import opener from './TreeNodeReducer'
import nodes from './nodes'
const rootReducer = combineReducers({
opener, nodes
});
export default rootReducer;
use mapStateToProps as above to get the nodes
regarding mapDispatchToProps
The only use case for bindActionCreators is when you want to pass some action creators down to a component that isn’t aware of Redux, and you don’t want to pass dispatch or the Redux store to it.
Since you already have the access to dispatch you can call it directly. Passing a map is a shorthand version of it. video

How to make AJAX request in redux

For all I know, I have to write request in action create. How to use a promise in action for submitting a request? I am getting data in action. Then new state is created in reducer. Bind action and reducer in connect. But I don't know how to use promise for request.
Action
import $ from 'jquery';
export const GET_BOOK = 'GET_BOOK';
export default function getBook() {
return {
type: GET_BOOK,
data: $.ajax({
method: "GET",
url: "/api/data",
dataType: "json"
}).success(function(data){
return data;
})
};
}
Reducer
import {GET_BOOK} from '../actions/books';
const booksReducer = (state = initialState, action) => {
switch (action.type) {
case GET_BOOK:
return state;
default:
return state;
}
};
export default booksReducer;
Container
How display data in container?
import React, { Component, PropTypes } from 'react';
import { connect } from 'react-redux';
import getBook from '../actions/books';
import Radium from 'radium';
import {Link} from 'react-router';
function mapStateToProps(state) {
return {
books: state.data.books,
};
}
function mapDispatchToProps(dispatch) {
return {
getBooks: () => dispatch(getBook()),
};
}
#Radium
#connect(mapStateToProps, mapDispatchToProps)
class booksPage extends Component {
static propTypes = {
getBooks: PropTypes.func.isRequired,
books: PropTypes.array.isRequired,
};
render() {
const {books} = this.props;
return (
<div>
<Link to={`/authors`}><MUIButton style="flat">All Authors</MUIButton></Link>
<ul>
{books.map((book, index) =>
<li key={index}>
<Link to={`/book/${book.name}`}><MUIButton style="flat"><div class="mui--text-black mui--text-display4">
"{book.name}"</div></MUIButton></Link>
<Link to={`/author/${book.author}`}><MUIButton style="flat"><div class="mui--text-black mui--text-display4">
{book.author}</div></MUIButton></Link>
</li>
)}
</ul>
</div>
);
}
}
export default booksPage;
Since you are already using redux you can apply redux-thunk middleware which allows you to define async actions.
Installation & usage: Redux-thunk
export function fetchBook(id) {
return dispatch => {
dispatch(setLoadingBookState()); // Show a loading spinner
fetch(`/book/${id}`, (response) => {
dispatch(doneFetchingBook()); // Hide loading spinner
if(response.status == 200){
dispatch(setBook(response.json)); // Use a normal function to set the received state
}else {
dispatch(someError)
}
})
}
}
function setBook(data) {
return { type: 'SET_BOOK', data: data };
}
You should use Async Actions described in Redux Documentation
Here an example of reducer for async action.
const booksReducer = (state = {}, action) => {
switch (action.type) {
case 'RESOLVED_GET_BOOK':
return action.data;
default:
return state;
}
};
export default booksReducer;
and then you create your Async Action.
export const getBook() {
return fetch('/api/data')
.then(response => response.json())
.then(json => dispatch(resolvedGetBook(json)))
}
export const resolvedGetBook(data) {
return {
type: 'RESOLVED_GET_BOOK',
data: data
}
}
Several Notes:
We could return Promise (instead of Object) in action by using redux-thunk middleware.
Don't use jQuery ajax library. Use other library specifically for doing that (e.g. fetch()). I use axios http client.
Remember, in redux you only use pure function in reducer. Don't make ajax call inside reducer.
Read the complete guide from redux docs.
You should be able to use dispatch inside the callback (if you pass it as an argument):
export default function getBook(dispatch) {
$.ajax({
method: "GET",
url: "/api/data",
dataType: "json"
}).success(function(data){
return dispatch({type:'GET_BOOK', data: data});
});
}
Then, pass dispatch to the action:
function mapDispatchToProps(dispatch) {
return {
getBooks: () => getBook(dispatch),
};
}
Now, you should have access to the action.data property in the reducer:
const booksReducer = (state = initialState, action) => {
switch (action.type) {
case GET_BOOK:
//action.data <--- here
return state;
default:
return state;
}
};
You might want to separate concerns, to keep action creators "pure".
Solution; write some middleware. Take this for example (using superagent).
import Request from 'superagent';
const successHandler = (store,action,data) => {
const options = action.agent;
const dispatchObject = {};
dispatchObject.type = action.type + '_SUCCESS';
dispatchObject[options.resourceName || 'data'] = data;
store.dispatch(dispatchObject);
};
const errorHandler = (store,action,err) => {
store.dispatch({
type: action.type + '_ERROR',
error: err
});
};
const request = (store,action) => {
const options = action.agent;
const { user } = store.getState().auth;
let method = Request[options.method];
method = method.call(undefined, options.url)
if (user && user.get('token')) {
// This example uses jwt token
method = method.set('Authorization', 'Bearer ' + user.get('token'));
}
method.send(options.params)
.end( (err,response) => {
if (err) {
return errorHandler(store,action,err);
}
successHandler(store,action,response.body);
});
};
export const reduxAgentMiddleware = store => next => action => {
const { agent } = action;
if (agent) {
request(store, action);
}
return next(action);
};
Put all this in a module.
Now, you might have an action creator called 'auth':
export const auth = (username,password) => {
return {
type: 'AUTHENTICATE',
agent: {
url: '/auth',
method: 'post',
resourceName: 'user',
params: {
username,
password
}
}
};
};
The property 'agent' will be picked up by the middleware, which sends the constructed request over the network, then dispatches the incoming result to your store.
Your reducer handles all this, after you define the hooks:
import { Record } from 'immutable';
const initialState = Record({
user: null,
error: null
})();
export default function auth(state = initialState, action) {
switch (action.type) {
case 'AUTHENTICATE':
return state;
case 'AUTHENTICATE_SUCCESS':
return state.merge({ user: action.user, error: null });
case 'AUTHENTICATE_ERROR':
return state.merge({ user: null, error: action.error });
default:
return state;
}
};
Now inject all this into your view logic. I'm using react as an example.
import React from 'react';
import ReactDOM from 'react-dom';
/* Redux + React utils */
import { createStore, applyMiddleware, bindActionCreators } from 'redux';
import { Provider, connect } from 'react-redux';
// thunk is needed for returning functions instead
// of plain objects in your actions.
import thunkMiddleware from 'redux-thunk';
// the logger middleware is useful for inspecting data flow
import createLogger from 'redux-logger';
// Here, your new vital middleware is imported
import { myNetMiddleware } from '<your written middleware>';
/* vanilla index component */
import _Index from './components';
/* Redux reducers */
import reducers from './reducers';
/* Redux actions*/
import actionCreators from './actions/auth';
/* create store */
const store = createStore(
reducers,
applyMiddleware(
thunkMiddleware,
myNetMiddleware
)
);
/* Taint that component with store and actions */
/* If all goes well props should have 'auth', after we are done */
const Index = connect( (state) => {
const { auth } = state;
return {
auth
};
}, (dispatch) => {
return bindActionCreators(actionCreators, dispatch);
})(_Index);
const provider = (
<Provider store={store}>
<Index />
</Provider>
);
const entryElement = document.getElementById('app');
ReactDOM.render(provider, entryElement);
All of this implies you already set up a pipeline using webpack,rollup or something, to transpile from es2015 and react, to vanilla js.
Consider using the new thunk API
export const load = createAsyncThunk(
'example/api',
async (arg, thunkApi) => {
const response = await fetch('http://example.api.com/api')
if (response.status === 200) {
const json = await response.json()
return json
},
)
Also, in the new redux template application, actions are part of the reducer/slice, and you can use extraReducers to response to events related to the async action status. It is much simpler using redux this way.
See documentation of async thunk here: https://redux.js.org/usage/writing-logic-thunks

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