Develop Reference

Problem when maping array - React with Redux Toolkit

I have the following problem: I use a fatch API to get all the products I have registered in my database (mongodb), then I store the result in a slice called products-slice which has an array as its initial state empty. Until then everything is in order. As I need information the time the homepage is loaded, I use the useEffect hook to fetch the products I have registered. Then I pass this array as props to a component, and make a map. The problem is that when the component loads, the information is not local.
código do backend
module.exports.fetchProduct = async (req, res) => {
try {
const products = await Product.find({});
if (products) {
res.json(products);
}
} catch (error) {
console.log(error);
}
};
productsActions.js
export const fetchProducts = () => {
return async (dispatch) => {
try {
const response = await fetch("http://localhost:xxxx/xxxxxx");
const data = await response.json();
let loadedProducts = [];
for (const key in data) {
loadedProducts.push({
id: data[key]._id,
productName: data[key].productName,
price: data[key].price,
imageUrl: data[key].imageUrl,
});
}
dispatch(setProducts(loadedProducts));
} catch (error) {
console.log(error);
}
};
};
home.jsx
import { useEffect } from "react";
import { useDispatch, useSelector } from "react-redux";
import { Container } from "react-bootstrap";
import {fetchProducts} from '../../store/actions/productsActions';
import Hero from "../hero/Hero";
import Footer from "../footer/Footer";
import DisplayProductsList from "../displayProduct/DisplayProductsList";
export default function Home() {
const productsInfo = useSelector((state) => state.products.products);
console.log(productsInfo);
const dispatch = useDispatch();
useEffect(() => {
dispatch(fetchProducts());
}, [dispatch]);
return (
<>
<Hero />
<DisplayProductsList products={productsInfo} />
<Container fluid>
<Footer></Footer>
</Container>
</>
);
}
product-slice.js
const initialState = {
products: [],
};
const productSlice = createSlice({
name: "product",
initialState,
reducers: {
setProducts(state, action) {
state.products.push(action.payload);
},
},
});
export const { setProducts } = productSlice.actions;
export default productSlice.reducer;
component where I'm mapping
export default function DisplayProductsList(props) {
console.log(props);
return (
props.products.map((product) => (
<DisplayProducts
key={product.id}
imageUrl={product.imageUrl}
name={product.productName}
price={product.price}
/>
))
);
}
console.log output in the above component
enter image description here

React test a component with saga

Hllo Guys, I'm having a bit trouble with testing my component
The problem is that I would like to test my React Native Component that uses saga to fetch data from server.
The Problem is that I do know what I'm supposed to do, I think I should mock my API calls in my test file but I do not know how :/
The component file is really simple, when mounted it dispatches action to fetch list on vehicles, and then it shows them in UI. And until that is fetched it shows loading text
Bellow are my current setup of components & test file.
Here is a screen component that fetches initial data on screen load
Screen Component
import React, { useContext, useEffect, useState } from 'react';
import { Platform, FlatList, View, ActivityIndicator, Text } from 'react-native';
import PropTypes from 'prop-types';
import { useDispatch, useSelector } from 'react-redux';
import { vehiclesActions } from '_store/vehicles';
export const MainScreen = ({ navigation }) => {
/**
* Redux selectors and dispatch
*/
const {
loading = true,
vehicles = [],
loadMore = false
} = useSelector((state) => state.vehicles);
/**
* Initial effect, fetches all vehicles
*/
useEffect(() => {
dispatch(
vehiclesActions.vehicleGet({
page: 1,
})
);
}, []);
const renderCard = () => {
return (<View><Text>Test</Text></View>)
}
if (loading) {
return (<View><Text>App Loading </Text></View>
}
return (
<View style={styles.wrapper}>
<View
style={
Platform.OS === 'ios' ? { marginTop: 30 } : { marginTop: 0, flex: 1 }
}
>
{!loading && (
<View style={Platform.OS === 'ios' ? {} : { flex: 1 }}>
<FlatList
testID={'flat-list'}
data={vehicles}
renderItem={renderCard}
/>
</View>
)}
</View>
</View>
);
};
MainScreen.propTypes = {
navigation: PropTypes.object
};
export default MainScreen;
My Vehicles Saga:
const api = {
vehicles: {
getVehicles: (page) => {
return api.get(`/vehicles/list?page=${page}`, {});
},
}
function* getVehicles(action) {
try {
const { page } = action.payload;
const { data } = yield call(api.vehicles.getVehicles, page);
yield put({ type: vehiclesConstants.VEHICLE_GET_SUCCESS, payload: data });
} catch (err) {
yield call(errorHandler, err);
yield put({ type: vehiclesConstants.VEHICLE_GET_FAIL });
}
}
export function* vehiclesSaga() {
yield takeLatest(vehiclesConstants.VEHICLE_GET_REQUEST, getVehicles);
}
Actions:
export const vehiclesActions = {
vehicleGet: payload => ({ type: vehiclesConstants.VEHICLE_GET_REQUEST, payload }),
vehicleGetSuccess: payload => ({ type: vehiclesConstants.VEHICLE_GET_SUCCESS, payload }),
vehicleGetFail: error => ({ type: vehiclesConstants.VEHICLE_GET_FAIL, error }),
}
Reducer
import { vehiclesConstants } from "./constants";
const initialState = {
vehicles: [],
loading: true,
};
export const vehiclesReducer = (state = initialState, action) => {
switch (action.type) {
case vehiclesConstants.VEHICLE_GET_REQUEST:
return {
...state,
loading: true,
};
case vehiclesConstants.VEHICLE_GET_SUCCESS:
return {
...state,
loading: false,
vehicles: action.payload,
};
}
}
My Test File
import 'react-native';
import React from 'react';
import {cleanup, render, fireEvent} from '#testing-library/react-native';
import AppScreen from '../../../../src/screens/App/index';
import {Provider} from 'react-redux';
import {store} from '../../../../src/store/configureStore';
describe('App List Component', () => {
beforeEach(() => jest.useFakeTimers());
afterEach(cleanup);
it('should render vehicle list page title', async () => {
const navigation = {
setParams: () => {},
navigate: jest.fn(),
};
const route = {
}
const component = (
<Provider store={store}>
<AppScreen route={route} navigation={navigation} />
</Provider>);
const {getByText, getByTestId} = render(component);
const pageTitle = await getByText('App Loading'); // this works fine
expect(pageTitle).toBeDefined();
});
it('should navigate to add vehicle', async () => {
const navigation = {
setParams: () => {},
navigate: jest.fn(),
};
const route = {
}
const component = (
<Provider store={store}>
<AppScreen route={route} navigation={navigation} />
</Provider>);
const {getByText, getByTestId} = render(component);
const flatList = await getByTestId('flat-list');// this throws error since flat list is still not shown, and loading is showing instead
});
Like I see above I cannot find element with testId flat-list, since component AppScreen it always show loading text, is there any way I could mock that API call and make this to work ?

Jest allows you to mock any module using jest.mock.
You have to write an alternative to axios.get like this
const vehiclesData = [
// ... put default data here
]
const delay = (ms, value) =>
new Promise(res => setTimeout(() => res(value), ms))
const mockAxiosGet = async (path) => {
let result = null
if (path.includes('vehicles/list') {
const query = new URLSearchParams(path.replace(/^[^?]+\?/, ''))
const page = + query.get('page')
const pageSize = 10
const offset = (page - 1)*pageSize
result = vehiclesData.slice(offset, offset + pageSize)
}
return delay(
// simulate 100-500ms latency
Math.floor(100 + Math.random()*400),
{ data: result }
)
}
Then modify the test file as
import 'react-native';
import React from 'react';
import {cleanup, render, fireEvent} from '#testing-library/react-native';
import axios from 'axios'
// enable jest mock on 'axios' module
jest.mock('axios')
import AppScreen from '../../../../src/screens/App/index';
import {Provider} from 'react-redux';
import {store} from '../../../../src/store/configureStore';
describe('App List Component', () => {
before(() => {
// mock axios implementation
axios.get.mockImplementation(mockAxiosGet)
})
beforeEach(() => jest.useFakeTimers());
afterEach(cleanup);
it('should render vehicle list page title', async () => {
const navigation = {
setParams: () => {},
navigate: jest.fn(),
};
const route = {
}
const component = (
<Provider store={store}>
<AppScreen route={route} navigation={navigation} />
</Provider>);
const {getByText, getByTestId} = render(component);
const pageTitle = await getByText('App Loading'); // this works fine
expect(pageTitle).toBeDefined();
});
it('should navigate to add vehicle', async () => {
const navigation = {
setParams: () => {},
navigate: jest.fn(),
};
const route = {
}
const component = (
<Provider store={store}>
<AppScreen route={route} navigation={navigation} />
</Provider>);
const {getByText, getByTestId} = render(component);
const flatList = await getByTestId('flat-list');// this throws error since flat list is still not shown, and loading is showing instead
});
For your use case, read more at Mocking Implementations

Redux Toolkit State issue when sending to child component

I am creating react redux application using redux toolkit and I'm passing some props to child component, it supposed to be one post because I'm using a map in parent component and passing one data to each component.
I'm trying to do Edit button and when clicking the "Edit button" trying to send ID to redux store but there is an error. If anyone know the answer please let me know.
Below is my redux slice:
import { createAsyncThunk, createSlice } from "#reduxjs/toolkit";
import axios from "axios";
const initialState = {
allPosts: [],
loading: "idle",
error: "",
currentId: "",
};
export const fetchAlltAsync = createAsyncThunk(
"allposts",
async (_, thunkAPI) => {
try {
const response = await axios.get("http://localhost:5000/posts/");
// The value we return becomes the `fulfilled` action payload
return response.data;
} catch (error) {
throw thunkAPI.rejectWithValue({ error: error.message });
}
}
);
export const postsingleAsync = createAsyncThunk(
"postsingleAsync",
async (post, { dispatch }) => {
const response = await axios.post("http://localhost:5000/posts/", post);
return response.data;
}
);
export const idsingleAsync = createAsyncThunk(
"idsingleAsync",
async (id, updatedpost) => {
const response = await axios.patch(
`http://localhost:5000/posts/${id}`,
updatedpost
);
return response.data;
}
);
export const postSlice = createSlice({
name: "posts",
initialState,
// The `reducers` field lets us define reducers and generate associated actions
reducers: {
// Use the PayloadAction type to declare the contents of `action.payload`
newsetcurrentId: (state, action) => {
state.currentId = action.payload;
},
},
// The `extraReducers` field lets the slice handle actions defined elsewhere,
// including actions generated by createAsyncThunk or in other slices.
extraReducers: (builder) => {
builder.addCase(fetchAlltAsync.pending, (state) => {
state.allPosts = [];
state.loading = "Loading";
});
builder.addCase(fetchAlltAsync.fulfilled, (state, action) => {
state.allPosts = action.payload;
state.error += "Loaded";
});
builder.addCase(fetchAlltAsync.rejected, (state, action) => {
state.allposts = "data not loaded";
state.loading = "error";
state.error = action.error.message;
});
builder.addCase(idsingleAsync.fulfilled, (state, action) => {
state.currentId = action.payload;
});
},
});
export const { setcurrentId, newsetcurrentId } = postSlice.actions;
// The function below is called a selector and allows us to select a value from
// the state. Selectors can also be defined inline where they're used instead of
// in the slice file. For example: `useSelector((state: RootState) => state.counter.value)`
export const selectCount = (state) => state.counter.value;
// We can also write thunks by hand, which may contain both sync and async logic.
// Here's an example of conditionally dispatching actions based on current state.
export const incrementIfOdd = (amount) => (dispatch, getState) => {};
export default postSlice.reducer;
Below is my parent component:
import React, { useEffect, useState } from "react";
import Post from "./Post";
import { useSelector, useDispatch } from "react-redux";
const Posts = ({ SETCURRENTID, CURENTID }) => {
// const dispatch = useDispatch();
const posts = useSelector((state) => state.posts.allPosts);
return (
<div>
{posts &&
posts.map(({ _id, ...rest }) => (
<Post key={_id} rest={rest} id={_id} />
))}
</div>
);
};
export default Posts;
This is my child component:
import React from "react";
import moment from "moment";
import { idsingleAsync, newsetcurrentId } from "../../features/postSlice";
import { useSelector, useDispatch } from "react-redux";
const Post = ({ rest, _id }) => {
const dispatch = useDispatch();
console.log(rest, "gff");
//const { id } = this.rest._id;
const handleClick = () => dispatch(newsetcurrentId());
return (
<div>
<h1>{rest.title}</h1>
<img
style={{ maxWidth: "250px", border: "12px solid purple" }}
alt="d"
src={rest.selectedFile}
/>
<h2>{moment(rest.createdAt).fromNow()}</h2>
<button onClick={() => dispatch(newsetcurrentId(rest._id))}> edit</button>
<h5>{rest.tags.map((tag) => `#${tag} `)}</h5>
<h5 onClick={() => {}}>{rest.likeCount}</h5>
<button onClick={() => {}}>Delete</button>
</div>
);
};
export default Post;
This is the redux error:
requestId(pin):undefined

TL;DR
Instead of rest._id , try passing the id prop to your newsetcurrentId dispatch:
const Post = ({ rest, id }) => { //Change _id to id
const dispatch = useDispatch();
const handleClick = () => dispatch(newsetcurrentId());
return (
<div>
<h1>{rest.title}</h1>
<img
style={{ maxWidth: "250px", border: "12px solid purple" }}
alt="d"
src={rest.selectedFile}
/>
<h2>{moment(rest.createdAt).fromNow()}</h2>
{/* pass id here */}
<button onClick={() => dispatch(newsetcurrentId(id))}> edit</button>
<h5>{rest.tags.map((tag) => `#${tag} `)}</h5>
<h5 onClick={() => {}}>{rest.likeCount}</h5>
<button onClick={() => {}}>Delete</button>
</div>
);
};
Explanation
When you are doing this destructuring:
posts.map(({ _id, ...rest }) => ( your rest object will actually contain all the post properties apart from _id so you don't actually have rest._id which you are trying to access on your Post child.
Additionally, you are passing id={_id} as a prop from the parent to the child, so you don't actually have an _id prop on your Post component (change it to id).

useState won't update the state when I set it in react

I need to render a component that has a route using react router. the first component has a button that when clicked needs to render another component that has state passed in from the first component. The page redirects but doesn't load. All of the data from the first component I want is passed in but it wont set state when I use setProfile(p). All the other console.log()s in the member component show all the data I expect but it won't set the state with this data.
import {useLocation} from "react-router-dom";
const Member = (props)=> {
const [user, setUser] = useState({});
const [profile, setProfile] = useState({});
const [user, setUser] = useState({});
const { state } = useLocation();
const [profile, setProfile] = useState({});
const dispatch = useDispatch();
const [list, setList] = useState([]);
const [posts, setPosts] = useState([]);
const [snInstance, setsnInstance] = useState({});
// run effect when user state updates
useEffect(() => {
const doEffects = async () => {
try {
// const p = await incidentsInstance.usersProfile(state.user, { from: accounts[0] });
// const a = await snInstance.getUsersPosts(state.user, { from: accounts[0] });
if (state && state.user) {
setUser(state.user);
}
const accounts = await MyWeb3.getInstance().getAccounts();
setAccounts(accounts);
console.log(accounts)
const incidents = MyWeb3.getInstance().getContract(Incidents)
const incidentsInstance = await MyWeb3.getInstance().deployContract(incidents);
const sn = MyWeb3.getInstance().getContract(SocialNet)
const snInstance = await MyWeb3.getInstance().deployContract(sn);
setsnInstance(snInstance);
const pro = socialNetworkContract.members[0]
console.log(pro)
const p = await incidentsInstance.usersProfile(pro, { from: accounts[0] });
const a = await snInstance.getUsersPosts(pro, { from: accounts[0] });
console.log(a)
console.log(p)
setProfile(p)
} catch (e) {
console.error(e)
}
}
doEffects();
}, [profile, state]);
const socialNetworkContract = useSelector((state) => state.socialNetworkContract)
return (
<div class="container">
<a target="_blank">Name : {profile.name}</a>
{socialNetworkContract.posts.map((p, index) => {
return <tr key={index}>
{p.message}
</tr>})}
</div>
)
}
export default Member;
This is the parent component I want to redirect from
const getProfile = async (member) => {
const addr = dispatch({ type: 'ADD_MEMBER', response: member })
console.log(member)
}
const socialNetworkContract = useSelector((state) => state.socialNetworkContract)
return (
<div>
{socialNetworkContract.posts.map((p, index) => {
return <tr key={index}>
<button onClick={() => getProfile(p.publisher)}>Profile</button>
</tr>})}
</div>
)
}
export default withRouter(Posts);
I have this component working when I don't have a dynamic route that needs data passing in from the parent component It's redirecting from.
My routes.js looks like
const Routes = (props) => {
return (
<Switch>
<Route path="/member" exact component={Member} />
<Route path="/posts" exact component={Posts} />
<Redirect exact to="/" />
</Switch>
)
}
export default Routes
This is the reducer
import { connect, useDispatch, useSelector } from "react-redux";
let init = {
posts:[],
post:{},
profiles:[],
profile:{},
members:[],
member:{}
}
export const socialNetworkContract = (state = init, action) => {
const { type, response } = action;
switch (type) {
case 'ADD_POST':
return {
...state,
posts: [...state.posts, response]
}
case 'SET_POST':
return {
...state,
post: response
}
case 'ADD_PROFILE':
return {
...state,
profiles: [...state.profiles, response]
}
case 'SET_PROFILE':
return {
...state,
profile: response
}
case 'ADD_MEMBER':
return {
...state,
members: [...state.members, response]
}
case 'SET_MEMBER':
return {
...state,
member: response
}
default: return state
}
};

It doesn't make any sense that you would dispatch({ type: 'ADD_MEMBER', response: member }) with a member object that came from the publisher property of a post. That info is already in your state. You probably need to be normalizing your state better so that you can select it where you need it.
You want to use the Link component from react-router-dom to navigate to a member's profile page. Your Route should render the correct profile based on an id or username property in the URL. Don't pass through the data when you redirect, just go to the correct URL. On that Member page you can get the user from the state by looking up the id.
In Posts:
<Link to={`/member/${p.publisher.id}`}><button>Profile</button></Link>
In Routes:
<Route path="/member/:id" component={Member} />
In Member:
const Member = () => {
const { id } = useParams();
const profile = useSelector((state) =>
state.socialNetworkContract.members.find((user) => user.id === id)
);
const dispatch = useDispatch();
useEffect(() => {
const doEffects = async () => {
if ( ! profile ) {
dispatch(loadUser(id));
}
};
doEffects();
}, [dispatch, profile, id]);

React Redux state array variable pass as prop to child component, either infinite loop or empty array

I am passing Redux state variable collection as props to PokeList.js,
using the useEffect hook to set state, but if I set props.collection as dependency
the array map function sees the props.collection as empty array, since I tried to
log out pokeData in the map function and gets nothing, if I remove the
props.collection dependency, it creates an infinite loop situation, I can console.log
the props.collection, which shows an empty array first, then the correct array,
how do I set the state correctly?
I have tried dispatching in PokeList.js, which has the same result,
also tried dirrectly initialize cardList = props.collection.map... but
get cardList undefined,
also tried using React.memo and set props as dependency
doesn't work either
//PokeList.js
import React, { useState, useEffect } from 'react';
import Card from 'react-bootstrap/Card';
import ListGroup from 'react-bootstrap/ListGroup';
const PokeList = (props) => {
const [cardList, setCardList] = useState();
console.log(props.collection)
useEffect(() => {
var newCardList = props.collection.map(pokeData => {
console.log(pokeData)
return (
<Card key={pokeData.id} style={{ width: '18rem' }}>
<Card.Img variant="top" src={pokeData.sprite} />
<Card.Body>
<Card.Title>{pokeData.Name}</Card.Title>
<ListGroup className="list-group-flush">
<ListGroup.Item>{'Height: ' + pokeData.height}</ListGroup.Item>
<ListGroup.Item>{'Weight: ' + pokeData.weight}</ListGroup.Item>
</ListGroup>
</Card.Body>
</Card>
)})
setCardList(newCardList)
}, [props.collection])
return (
<div>
{cardList}
</div>
)
}
export default PokeList;
//Search.js
import React, { useEffect } from 'react';
import { Container } from 'react-bootstrap';
import { useDispatch, useSelector } from 'react-redux';
import PokeList from './pokedex/PokeList';
import * as pokedexActions from './pokedex/actions/PokedexActions';
const Search = () => {
const dispatch = useDispatch();
useEffect(() => {
dispatch(pokedexActions.getLimitNames(5))
}, [dispatch])
const collection = useSelector(state => state.pokedex.collection);
return (
<div>
<Container>
<h2>Search</h2>
<PokeList collection={collection}/>
</Container>
</div>
);
}
export default Search;
// reducer.js
import { GET_LIMIT_NAMES } from '../actions/PokedexActions';
const initialState = {
collection: []
};
export default (state = initialState, action) => {
switch (action.type) {
case GET_LIMIT_NAMES:
return {
collection: action.data
};
default:
return state;
}
};
// action.js
import Pokemon from '../Pokemon';
export const GET_LIMIT_NAMES = "GET_LIMIT_NAMES";
export const getLimitNames = (limit = 100) => {
// redux-thunk
return async dispatch => {
try {
const allResponse = await fetch(`https://pokeapi.co/api/v2/pokemon/?limit=${limit}`);
const allUrlsData = await allResponse.json();
// console.log(allUrlsData.results);
const collection = [];
Promise.all(allUrlsData.results.map(urlData => {
var pokemon;
fetch(urlData.url).then(resp =>
resp.json()
).then(data => {
// console.log(data);
pokemon = new Pokemon(data);
// pokemon.log();
collection.push(pokemon)
}).catch(err => {
console.log(err);
})
return collection;
}))
// console.log(collection)
dispatch({
type: GET_LIMIT_NAMES,
data: collection
});
} catch (err) {
console.log(err);
}
};
};
if I try to directly render the map result, nothing appeared, the map function
still only gets the empty array,
// PokeList.js
import React from 'react';
import Card from 'react-bootstrap/Card';
import ListGroup from 'react-bootstrap/ListGroup';
import './Pokedex.css'
const PokeList = (props) => {
console.log('props.collection', props.collection)
return (
// <div className='poke-list'>
// {cardList}
// </div>
<div className='poke-list'>
{props.collection.map(pokeData => {
return (
<Card key={pokeData.id} style={{ width: "18rem" }}>
<Card.Img variant="top" src={pokeData.sprite} />
<Card.Body>
<Card.Title>{pokeData.Name}</Card.Title>
<ListGroup className="list-group-flush">
<ListGroup.Item>{"Height: " + pokeData.height}</ListGroup.Item>
<ListGroup.Item>{"Weight: " + pokeData.weight}</ListGroup.Item>
</ListGroup>
</Card.Body>
</Card>
);
})}
</div>
)
}
export default PokeList;
if I remove the [props.collection] dependency, it creates the infinite loop
situation, but the components are rendering

The issue here is that every time Search renders, collection is created and passed to PokeList. Then PokeList is using that collection (new on every render, remember) and using it as a dependency of your hook. This means that every time Search renders, the hook in PokeList will run.
Simply use collection prop to render the Component tree inside PokeList:
const PokeList = props => {
console.log(props.collection);
return (
<div>
{props.collection.map(pokeData => {
return (
<Card key={pokeData.id} style={{ width: "18rem" }}>
<Card.Img variant="top" src={pokeData.sprite} />
<Card.Body>
<Card.Title>{pokeData.Name}</Card.Title>
<ListGroup className="list-group-flush">
<ListGroup.Item>{"Height: " + pokeData.height}</ListGroup.Item>
<ListGroup.Item>{"Weight: " + pokeData.weight}</ListGroup.Item>
</ListGroup>
</Card.Body>
</Card>
);
})}
</div>
);
};

turns out the problem is in Acions.js Problem.all
by changing into for loop and await for all fetches solves the
not empty array problem
for (var i=0; i<allUrlsData.results.length; i++) {
const res = await fetch(allUrlsData.results[i].url)
const resData = await res.json()
const pokemon = new Pokemon(resData)
collection.push(pokemon)
}