Develop Reference

Why is my component unable to access data from my reducer?

I am writing a React app in which somebody can sign up as a business or user, and a user is able to search for a business by name. I do not understand why I am getting an error when trying to render my search component, saying "TypeError: Cannot read properties of undefined (reading 'toLowerCase')". I do not understand why I am getting this error because I believe I am passing in the appropriate data via my reducers and the Redux store. This is my search component:
import React, { Component } from 'react';
import { connect } from 'react-redux';
import BusinessCard from '../Business/BusinessCard'
import { Card } from 'semantic-ui-react';
class Businesses extends Component {
state = {newSearch: ""}
handleInputChange = e => {
this.setState({newSearch: e.target.value})
}
render() {
const { businessesReducer} = this.props;
let businessesMatch = businessesReducer.businesses.filter( (business ) => business.name.toLowerCase().includes(this.state.newSearch.toLowerCase()))
return (
<div>
<input placeholder="Search Events and Services Near You" value={this.state.newSearch} name="businessName" type="text" onChange={this.handleInputChange} />
<Card.Group itemsPerRow={3}>
{ businessesMatch.map((business, id) => <BusinessCard key={id} business={business} />)}
</Card.Group>
</div>
)
}
}
const mapStateToProps = (state) => {
return ({
businessesReducer: state.businessesReducer
})
}
export default connect(mapStateToProps)(Businesses);
My businesses reducer:
const initialState =
{
businesses:[],
isLoading: false
}
export default (state = initialState, action) => {
switch (action.type) {
case 'LOADING':
return {
...state,
isLoading: true
}
case "GET_ALL_BUSINESSES_SUCCESS":
return { ...state,
businesses: action.businesses,
isLoading: false
}
default:
return state
}
}
BusinessCard.js (which I am trying to render per the user's search)
import React, { Component } from 'react';
import { Card } from 'semantic-ui-react';
import { connect } from 'react-redux';
class BusinessCard extends Component {
constructor(props) {
super(props);
}
render(){
const { business, businessesReducer } = this.props;
return(
<Card>
<div key={business.id} >
<Card.Content>
<Card.Header><strong>{business.name}</strong></Card.Header>
</Card.Content>
</div>
</Card>
)
}
}
const mapStateToProps = state => {
return {
businesses: state.businesses,
businessesReducer: state.businessesReducer
}
}
export default connect(mapStateToProps)(BusinessCard);
And App.js
import { getAllBusinesses } from './actions/business/business';
import { BrowserRouter as Router, Route, Switch} from 'react-router-dom';
import history from './history';
class App extends React.Component {
componentDidMount() {
this.props.getAllBusinesses();
}
render() {
return (
<Router history={history}>
<div className="App">
<NavBar />
<Switch>
<Route exact path="/" component={Home}/>
<Route path="/about" component={About} />
<Route path="/services" component={Services} />
<Route path="/shop" component={Shop}/>
<Route path="/login-signup" component={LoginContainer}/>
<Route path="/signup" component={Signup}/>
<Route path="/business-signup" component={BusinessSignup}/>
<Route path="/professional-signup" component={ProfessionalSignup}/>
<Route path="/search" component={Businesses}/>
</Switch>
</div>
</Router>
)
}
}
const mapStateToProps = (state) => {
return {
businessesReducer: state.businessesReducer
}
}
export default connect(mapStateToProps, {getAllBusinesses})(App);
Does anybody have any idea why my search component cannot access "business" and its properties? Everything looks correct to me.

1: It would be good if you could show getAllBusinesses.
2: Please make sure if data exists in your store, you can use redux-dev-tools for that.
3: The first time that your component renders there is no data in your store and it's just an empty array so please first check if name exists and has value then try to convert it to lower case.
It would be something like this:
let businessesMatch = businessesReducer.businesses.filter(
(business) =>
business.name &&
business.name
.toLowerCase()
.includes(this.state.newSearch.toLowerCase())
);
Or if with optional chaining:
let businessesMatch = businessesReducer.businesses.filter((business) =>
business?.name
.toLowerCase()
.includes(this.state.newSearch.toLowerCase())
);
If none of these help please provide more information like a code sandbox.

Cannot route to required React Component using React-Router-DOM

I am trying to route to the component "Products" from my Homepage as per the product id from the item list from the Home Component. My page is getting routed to 'localhost:3000/id' but it is not getting the Products component. There are no errors that I faced. I fetched the data from the fake API and displayed the products on the home page. After clicking the product I want the page to route to "Product" component. The address is routing as expected but the component is not loading.
import React, { Component } from "react";
import {
BrowserRouter as Router,
Switch,
Route,
Link
} from "react-router-dom";
import Products from "./Products";
interface Props {}
interface ResponseData {
id: number;
price: number;
description: string;
image: string;
}
interface State {
response: ResponseData[];
}
export default class Home extends React.PureComponent<Props, State> {
constructor(props: Props) {
super(props);
this.state = {
response: [],
};
}
getProductsData = async () => {
const apiResponse = await fetch("https://fakestoreapi.com/products");
console.log(apiResponse);
const responseData = await apiResponse.json();
this.setState({
response: responseData,
});
};
componentDidMount() {
this.getProductsData();
}
render() {
const { response } = this.state;
if (response.length === 0) {
return <div className="loader">Loading the items....... </div>;
}
return (
<div >
<div className="product-list">
{response.map((resp) => (
<Switch>
<Link className = "product-cards"
to={`${resp.id}`} >
<Route path={`${resp.id}`} component={Products}/>
<div className="product-cards">
<img src={resp.image} />
<div className="product-description">{resp.description}</div>
<div className="product-price">{resp.price}</div>
</div>
</Link>
</Switch>
))}
</div>
</div>
);
}
}

You probably need to replace your switch routes to App component and in this Home component just use a Link to redirect to the path you want.
function App() {
return (
<Switch>
<Route exact path="/" component={ Home } />
<Route path="/:id" component={ Products } />
</Switch>
);
}
Home component return should be something like this:
return (
<div className="product-list">
{response.map((resp) => (
<Link
className = "product-cards"
to={`/${resp.id}`}
>
<div className="product-cards">
<img src={resp.image} />
<div className="product-description">{resp.description}</div>
<div className="product-price">{resp.price}</div>
</div>
</Link>
))}
</div>
);

react combine differents wrappers

We are starting a new project in React.
And we need to use:
React Context API
i18n (react.i18nex)
GraphQL (Apollo client)
Redux
CCS-in-JS (styled-components or aphodite)
The thing is that any of this implementation wraps a component and pass it some props or use functions as children.
And I want to keep my components as decoupled and clean as possible.
How can I structure the wrappers?
Example
Home
<Home {...props} />
Context:
<ThemeContext.Consumer>
{ theme=> <Home {...theme} programa={theme} /> }
</ThemeContext.Consumer>
i18n:
<I18n>
{t => <Home text={t("translated text")} /> }
</I18n>
GraphQL:
<Query query={GET_PROGRAMA}>
{({ data }) => <Home data={data} />}
</Query>
Redux:
const mapStateToProps = state => ({
user: "some user"
});
export default connect(
mapStateToProps,
)(Home);
As you can see, the Home component receives isolated props from many sources.
How can I manage ir and keep it decoupled? There is some kind of composer?
Thank you!

I think you can convert this into an HOC that will handle all of the component wrapping for you:
const withWrappers = WrappedComponent => {
return class extends React.Component {
render () {
return (
<ThemeContext.Consumer>
{ theme =>
<I18n>
{ t =>
<Query query={GET_PROGRAMA}>
{ ({ data }) =>
<WrappedComponent
{...this.props}
{...theme}
programa={theme}
data={data}
text={t("translated text")}
/>
}
</Query>
}
</I18n>
}
</ThemeContext.Consumer>
)
}
}
}
Usage:
class Home extends React.Component {
render () {
return (
<div>Home</div>
)
}
}
export default withWrappers(Home);

Thanks for your help! All of you.
I've implemented a HOC, the same as you porposed to me, and keep the GraphQL components outside:
import React from "react";
import PropTypes from "prop-types";
import { mergeStyles } from "js/utils";
import { I18n } from "react-i18next";
import { TemplateContext } from "js/template-context";
const Wrapper = ({ Component, getStylesFromTemplate }) => props => {
const { classes } = props;
return (
<TemplateContext.Consumer>
{programa => {
const { template } = programa;
const stylesFromTemplate = getStylesFromTemplate(template);
const styles = mergeStyles({ classes, stylesFromTemplate });
return (
<I18n>
{(t, { i18n }) => {
return (
<Component
t={t}
styles={styles}
programa={programa}
{...props}
/>
);
}}
</I18n>
);
}}
</TemplateContext.Consumer>
);
};
Wrapper.propTypes = {
classes: PropTypes.object.isRequired
};
export default Wrapper;
Again, thank you so much!

How to pass the state of the page to other React?

I want to know how I can pass a status from one page to another page for if used in the other way.
My first page Body.js (Which I handle the state):
import React from 'react';
import './Body.css';
import axios from 'axios';
import { Link } from "react-router-dom";
import User from './User';
class Body extends React.Component {
constructor (){
super();
this.state ={
employee:[],
employeeCurrent:[],
}
}
componentDidMount(){
axios.get('http://127.0.0.1:3004/employee').then(
response=>this.setState({employee: response.data})
)
}
getName = () => {
const {employee} = this.state;
return employee.map(name=> <Link className='link' to={`/user/${name.name}`}> <div onClick={()=>this.add(name)} key={name.id} className='item'> <img className='img' src={`https://picsum.photos/${name.name}`}></img> <h1 className='name'> {name.name} </h1></div> </Link>)
}
add = (name) => {
const nam = name;
this.state.employeeCurrent.push(nam)
console.log(this.state.employeeCurrent)
}
render(){
return(
<div className='body'>
{this.getName()}
</div>
)
}
}
export default Body;
My second page which I want to get the state called employeeCurrent:
import React from 'react';
import Header from './Header';
import Body from './Body';
class User extends React.Component {
constructor (props){
super(props);
this.props ={
employeeCurrent:[],
}
}
render(){
return(
<div >
{this.props.employeeCurrent}
</div>
)
}
}
export default User;
I'm using the React Router, it looks like this:
import React, { Component } from 'react';
import { BrowserRouter as Router, Route, Link } from "react-router-dom";
import './App.css';
import Home from './Home';
import User from './User';
const AppRouter = () => (
<Router>
<div className='router'>
<Route exact path="/" component={Home}/>
<Route path="/user/:id" component={User}/>
</div>
</Router>
);
export default AppRouter;
My project is:
Home page, where you have users, obtained from the API, all users have attributes (name, age, city and country). Saved in employeeCurrent variable:
What I want is: grab these attributes from the clicked user and play on the user page:
Someone would can help me PLEASE?????

Like I explained earlier, you need to lift the state up:
AppRouter (holds the state and passes it to children)
class AppRouter extends React.Component {
state = {
employeeCurrent: [],
employee: []
};
componentDidMount() {
axios
.get("http://127.0.0.1:3004/employee")
.then(response => this.setState({ employee: response.data }));
}
add = name => {
this.setState(prevState => {
const copy = prevState.employeeCurrent.slice();
copy.push(name);
return {
employeeCurrent: copy
};
});
};
render() {
return (
<Router>
<div className="router">
<Route
exact
path="/"
render={props => (
<Home
{...props}
add={this.add}
employee={this.state.employee}
currentEmployee={this.state.currentEmployee}
/>
)}
/>
<Route
path="/user/:id"
component={props => (
<User
{...props}
employee={this.state.employee}
currentEmployee={this.state.currentEmployee}
/>
)}
/>
</div>
</Router>
);
}
}
Body and User (receive parent state as props together with updater functions):
class Body extends React.Component {
getName = () => {
const { employee, add } = this.props;
return employee.map(name => (
<Link className="link" to={`/user/${name.name}`}>
{" "}
<div onClick={() => add(name)} key={name.id} className="item">
{" "}
<img
className="img"
src={`https://picsum.photos/${name.name}`}
/>{" "}
<h1 className="name"> {name.name} </h1>
</div>{" "}
</Link>
));
};
render() {
return <div className="body">{this.getName()}</div>;
}
}
class User extends React.Component {
render() {
// you will need to map employeeCurrent somehow
return <div>{this.props.employeeCurrent}</div>;
}
}

React js: can I pass data from a component to another component?

I'm new to React and I'm still learning it. I'm doing a personal project with it.
Let me explain my problem:
I have a component called <NewReleases /> where I make an ajax call and take some datas about some movies out on cinemas today. (I take title, poster img, overview etc...) I put all the data in <NewReleases /> state, so that state becomes an object containing an object for each movie and each object contains title poperty, poster property etc... Then I render the component so that it looks like a grid made by movies posters, infos and so on. And this works well.
Then I need a component <Movie /> to take some datas from the state of <NewReleases /> and render them on the HTML. I read other questions where people were having a similar problem, but it was different because they had a children component that was rendered by the parent component. And in that way, people suggested to pass state as props. I can't do that because my <Movie /> component is not rendered by <NewReleases />. <NewReleases /> makes the ajax call and only renders a JSX grid based on the retrieved data.
On index.js I have setup the main page this way:
import React from 'react';
import ReactDOM from 'react-dom';
import {BrowserRouter, Switch, Route} from 'react-router-dom';
import {Home} from './home';
import {Movie} from './movie';
import './css/index.css';
class App extends React.Component {
render() {
return(
<BrowserRouter>
<Switch>
<Route path={'/movie/:movieTitle'} component={Movie} />
<Route path={'/'} component={Home} />
</Switch>
</BrowserRouter>
);
}
}
ReactDOM.render(
<App />,
document.getElementById('root')
);
(You can't see <NewReleases /> here because it is rendered inside of <Home /> component, which also renders a header and a footer.)
So when I click on a movie rendered by <NewReleases />, the app will let me go on localhost:3000/movie/:movieTitle where :movieTitle is a dynamic way to say the title of the movie (so for example if I click the poster of Star Wars rendered by <NewReleases />, I will go on localhost:3000/movie/StarWars). On that page I want to show detailed infos about that movie. The info are stored in <NewReleases /> state but I can't have access to that state from <Movie /> (I guess).
I hope you got what I want to achieve. I don't know if it is possible. I had an idea: on the <Movie /> I could do another ajax call just for the movie that I want but I think it would be slower and also I don't think it would be a good solution with React.
Note that I'm not using Redux, Flux etc... only React. I want to understand React well before to move to other technologies.

The way you wanna do is more complicated. With parents componentes that's easy to do. And with Redux is much more easy.
But, you wanna this way. I think if you have a state in the app, pass to home a props to set a movie-state and pass this movie-state to component Move, works fine.
The problem is that Route does't pass props. So there is a extensible route you can do. In the code below I get from web this PropsRoute.
import React from 'react';
import ReactDOM from 'react-dom';
import {BrowserRouter, Switch, Route} from 'react-router-dom';
import {Home} from './home';
import {Movie} from './movie';
import './css/index.css';
class App extends React.Component {
constructor() {
super();
this.state = {
movie: {}
}
this.setMovie = this.setMovie.bind(this);
}
setMovie(newMovie) {
this.setState({
movie: newMovie
});
}
render() {
return(
<BrowserRouter>
<Switch>
<PropsRoute path={'/movie/:movieTitle'} movie={this.state.movie} component={Movie} />
<PropsRoute path={'/'} component={Home} setMovie={this.setMovie} />
</Switch>
</BrowserRouter>
);
}
}
ReactDOM.render(
<App />,
document.getElementById('root')
);
-----
const renderMergedProps = (component, ...rest) => {
const finalProps = Object.assign({}, ...rest);
return (
React.createElement(component, finalProps)
);
}
const PropsRoute = ({ component, ...rest }) => {
return (
<Route {...rest} render={routeProps => {
return renderMergedProps(component, routeProps, rest);
}}/>
);
}
I thinks this can solve your problem.

Here's a quick example. Store your state in a parent component and pass down the state down to your components. This example uses React Router 4, but it shows how you can pass down the setMovie function and movie information via state to one of your child components. https://codepen.io/w7sang/pen/owVrxW?editors=1111
Of course, you'll have to rework this to match your application, but a basic run down would be that your home component should be where you're grabbing your movie information (via AJAX or WS) and then the set function will allow you to store whatever information you need into the parent component which will ultimately allow any child components to access the information you have stored.
const {
BrowserRouter,
Link,
Route,
Switch
} = ReactRouterDOM;
const Router = BrowserRouter;
// App
class App extends React.Component{
constructor(props) {
super(props);
this.state = {
movie: {
title: null,
rating: null
}
};
this.setMovie = this.setMovie.bind(this);
}
setMovie(payload) {
this.setState({
movie: {
title: payload.title,
rating: payload.rating
}
});
}
render(){
return(
<Router>
<div className="container">
<Layout>
<Switch>
<Route path="/select-movie" component={ () => <Home set={this.setMovie} movie={this.state.movie} />} />
<Route path="/movie-info" component={()=><MovieInfo movie={this.state.movie}/>} />
</Switch>
</Layout>
</div>
</Router>
)
}
}
//Layout
const Layout = ({children}) => (
<div>
<header>
<h1>Movie App</h1>
</header>
<nav>
<Link to="/select-movie">Select Movie</Link>
<Link to="/movie-info">Movie Info</Link>
</nav>
<section>
{children}
</section>
</div>
)
//Home Component
const Home = ({set, movie}) => (
<div>
<Movie title="Star Wars VIII: The Last Jedi (2017)" rating={5} set={set} selected={movie} />
<Movie title="Star Wars VII: The Force Awakens (2015)" rating={5} set={set} selected={movie} />
</div>
)
//Movie Component for displaying movies
//User can select the movie
const Movie = ({title, rating, set, selected}) => {
const selectMovie = () => {
set({
title: title,
rating: rating
});
}
return (
<div className={selected.title === title ? 'active' : ''}>
<h1>{title}</h1>
<div>
{Array(rating).fill(1).map(() =>
<span>★</span>
)}
</div>
<button onClick={selectMovie}>Select</button>
</div>
)
}
//Movie Info
//You must select a movie before movie information is shown
const MovieInfo = ({movie}) => {
const {
title,
rating
} = movie;
//No Movie is selected
if ( movie.title === null ) {
return <div>Please Select a Movie</div>
}
//Movie has been selected
return (
<div>
<h1>Selected Movie</h1>
{title}
{Array(rating).fill(1).map(() =>
<span>★</span>
)}
</div>
)
}
ReactDOM.render(<App />,document.getElementById('app'));
nav {
margin: 20px 0;
}
a {
border: 1px solid black;
margin-right: 10px;
padding: 10px;
}
.active {
background: rgba(0,0,0,0.2);
}
<div id="app"></div>

Create a manual object store to get/set the movie information and use it. That's it. Try the following code. That should answer all your questions. Click on any of the new releases, it will redirect to movie info screen with all the details. If you feel bad about the new releases data always refreshing, you may have to create another store, then get/set the data by checking the data exist in store.
Note: Using store and using title(duplicates may occur) in browser URL makes some problems when user refreshes the browser. For that, use id in browser URL, fetch the details using AJAX call and set that details in store.
//store for movie info
const movieInfoStore = {
data: null,
set: function(data) {
this.data = data;
},
clear: function() {
this.data = null;
}
};
class MovieInfo extends React.Component {
componentWillUnmount() {
movieInfoStore.clear();
}
render() {
return (
<div>
<pre>
{movieInfoStore.data && JSON.stringify(movieInfoStore.data)}
</pre>
<button onClick={() => this.props.history.goBack()}>Go Back</button>
</div>
)
}
}
MovieInfo = ReactRouterDOM.withRouter(MovieInfo);
class NewReleases extends React.Component {
handleNewReleaseClick(newRelease) {
movieInfoStore.set(newRelease);
this.props.history.push(`/movie/${newRelease.title}`);
}
render() {
const { data, loading } = this.props;
if(loading) return <b>Loading...</b>;
if(!data || data.length === 0) return null;
return (
<ul>
{
data.map(newRelease => {
return (
<li onClick={() => this.handleNewReleaseClick(newRelease)}>{newRelease.title}</li>
)
})
}
</ul>
)
}
}
NewReleases = ReactRouterDOM.withRouter(NewReleases);
class Home extends React.Component {
constructor(props) {
super(props);
this.state = {
newReleases: [],
newReleasesLoading: true
};
}
componentDidMount() {
setTimeout(() => {
this.setState({
newReleases: [{id: 1, title: "Star Wars"}, {id: 2, title: "Avatar"}],
newReleasesLoading: false
});
}, 1000);
}
render() {
const { newReleases, newReleasesLoading } = this.state;
return (
<NewReleases data={newReleases} loading={newReleasesLoading} />
)
}
}
class App extends React.Component {
render() {
const { BrowserRouter, HashRouter, Switch, Route } = ReactRouterDOM;
return (
<HashRouter>
<Switch>
<Route path="/movie/:movieTitle" component={MovieInfo} />
<Route path="/" component={Home} />
</Switch>
</HashRouter>
)
}
}
ReactDOM.render(<App />, document.getElementById("root"));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<script src="https://unpkg.com/react-router-dom/umd/react-router-dom.min.js"></script>
<div id="root"></div>