Develop Reference

Display a new component with button click

Im making my first react ptoject. Im new in JS, HTML, CSS and even web app programing.
What i try to do, is to display some infomration on button click.
I have an API, that looks like this:
endpoint: https://localhost:44344/api/Projects
My Data from it:
[{"id":1,"name":"Mini Jira","description":"Description for first project in list","tasks":null},{"id":2,"name":"Farm","description":"Description for second one","tasks":null}]
And im fine with that, i can get it easily by axios in my react app.
Now i will show you my Project.js Component:
import React, { Component } from "react";
import { ListGroupItem, Button, ButtonToolbar } from "react-bootstrap";
import ProjectDetails from "./ProjectDetails";
class Project extends Component {
render() {
return (
<ButtonToolbar>
<ListGroupItem>{this.props.project.name}</ListGroupItem>
<Button onClick={Here i want to display new component with details }bsStyle="primary">Details</Button>
</ButtonToolbar>
);
}
}
export default Project;
I have all data from api in project type.
My question is, how to display component that i named ProjectDetails.js on button click? I want to show all data stored in project from my api in separate view (new page or somethig like that).
View looks like this:
Thanks for any advices!
EDIT:
based on #Axnyff answer, i edited Project.js. it works ok. But when i want to (for testing) displat project.name, i get error map of undefined. My ProjectDetails.js:
import React, { Component } from "react";
class ProjectDetails extends Component {
state = {};
render() {
return <li>{this.props.project.name}</li>;
}
}
export default ProjectDetails;
EDIT2:
In Project.js in #Axnyff answet i just edited that line:
{this.state.showDetails && (
<ProjectDetails project={this.props.project} />
)}
i passed project by props, now it works like i want too. After click it displays project.name that i clicked on.

You should use state in your React component.
Let's create a field called showDetails in your state.
You can initialize it in your constructor with
constructor(props) {
super(props); // needed in javascript constructors
this.state = {
showDetails: false,
};
}
Then you need to modify the onClick to set that state to true
<Button onClick={() => this.setState({ showDetails : true })} bsStyle="primary">Details</Button>
And then use that state to show or not the ProjectDetails:
{ showDetails && <ProjectDetails /> }
The full component should look like
import React, { Component } from "react";
import { ListGroupItem, Button, ButtonToolbar } from "react-bootstrap";
import ProjectDetails from "./ProjectDetails";
class Project extends Component {
constructor(props) {
super(props); // needed in javascript constructors
this.state = {
showDetails: false,
};
}
render() {
return (
<ButtonToolbar>
<ListGroupItem>{this.props.project.name}</ListGroupItem>
<Button onClick={() => this.setState({ showDetails : true })} bsStyle="primary">Details</Button>
{ this.state.showDetails && <ProjectDetails /> }
</ButtonToolbar>
);
}
}
export default Project;
You can then modify the logic to add a toggling effect etc.
If you haven't done it, you should probably follow the official tutorial

function Bar() {
return <h1>I will be shown on click!</h1>;
}
class Foo extends React.Component {
constructor() {
super();
this.state = { showComponent: false };
}
handleClick = () => {
this.setState({ showComponent: !this.state.showComponent });
};
render() {
return (
<div>
{this.state.showComponent && <Bar />}
<button onClick={this.handleClick}>click</button>
</div>
);
}
}
ReactDOM.render(<Foo />, document.getElementById("root"));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>

Render a new Component without using router

I've created an application to React, and when it starts, the App component is rendered. I would like that when the user clicks on a button or link, the button or link has to be in the App component when clicking on that link, another component will be rendered but not inside the App component but only the new component will be rendered in the same URL. As for this new component, it has to have a similar button so that when the user clicks, only the App component is rendered and this component that the user has clicked on is not rendered, only the App component.
I do not know if I explained myself correctly. Ask me any question if you need some clarification.
My App component is the following:
import React, { Component } from 'react';
import Touch from './Touch';
import '../App.css';
class App extends Component{
render() {
return(
<div>
<div className="wrapper" >
<button >NewComponent</button><NewComponent />???
<h1>Google Cloud Speech with Socket.io</h1>
<p id="ResultText"><span className="greyText">No Speech to Text yet</span></p>
</div>
<div className="buttonWrapper" >
<button className="btn" id="startRecButton" type="button"> Start recording</button>
<button className="btn" id="stopRecButton" type="button"> Stop recording</button>
</div>
</div>
);
}
}
export default App
My index.js is the following:
import React from 'react';
import ReactDOM from 'react-dom';
import './App.css';
import App from './components/App.js';
import registerServiceWorker from './registerServiceWorker';
ReactDOM.render(<App />, document.getElementById('root'));
registerServiceWorker();

If you really don't want to use react-router you will need to store a value in the component's state and change the rendering method to reflect which button was pressed. If you want each of those component to include the button you need to switch, do the following :
class App extends Component {
constructor(props){
super(props);
this.state = {renderA: false,};
}
handleClick = (event) => {
this.setState((prevState) => ({renderA: !prevState.renderA}));
};
render = () => {
return(
<div>
{this.state.renderA ?
<ComponentA handleClick={this.handleCLick}/>:
<ComponentB handleClick={this.handleCLick}/>
}
</div>
);
};
} export default App;
// ComponentA
class ComponentA extends Component {
render = () => {
return(
<div>
// what you want inside your first page here
<button onClick={this.props.handleClick}
</div>
);
}
} export default ComponentA;
// ComponentB
class ComponentB extends Component {
render = () => {
return(
<div>
// what you want inside your second page here
<button onClick={this.props.handleClick}
</div>
);
}
} export default ComponentB;
But using react-router might also suits your case, and if you are going to write a large app, you should use it instead of rendering differents children components within the same one, based on users inputs.

If the URL stay the same, I don't think React-Router might help you.
If you want that App Component is not loaded, I think you should create two more Component, a Wrapper one, and the new component you want to display (from now on newComponent). What I suggest is:
Creating a property isButtonClicked inside the state of the Wrapper Component;
Creating a function handleButtonClick() inside the Wrapper Component:
handleButtonClick() => {
let isButtonClicked = !this.state.isButtonClicked;
this.setState({ isButtonClicked });
}
In the render() method of the Wrapper component, you write something like this:
render() {
if (this.state.isButtonClicked)
return <App />
else
return <NewComponent />
}
Then, in both App and NewComponent, if you click on the button, you call the this.props.handleButtonClick(), which will lead to a change of the state of Wrapper Component, therefore to a change of what is shown on the screen.

How to preserve referencies when Component is exported via a function?

Documentation describes how to add a ref to a class component when using ReactJS version 16.3+.
Here is a simplified and working example using two files:
MyForm.js file:
import React, { Component } from 'react';
import MyInput from "./MyInput";
class MyForm extends Component {
constructor(props) {
super(props);
this.myInput = React.createRef();
this.onClick = this.onClick.bind(this);
}
onClick(){
console.log(this.myInput.current.isValid());
}
render() {
return (
<div>
<MyInput ref={this.myInput} />
<button onClick={this.onClick}>Verify form</button>
</div>
);
}
}
export default MyForm;
MyInput.js file
import React, { Component } from 'react';
class MyInput extends Component {
isValid(){
return true;
}
render() {
return (
<div>
Name :
<input type="text" />
</div>
);
}
}
export default MyInput;
It works fine, console displays true when I click on MyForm button. But as soon as I add a function just before exporting my Component, errors are thrown. As example, I add a translation via react-i18n
MyInput.js file with export using a function
class MyInput extends Component {
isValid(){
return true;
}
render() {
const {t} = this.props;
return (
<div>
{t("Name")}
<input type="text" />
</div>
);
}
}
export default translate()(MyInput); // <=== This line is changing
Now, when I click on button, an error is thrown:
TypeError: this.myInput.current.isValid is not a function
The error disappear when I remove translate() in the last line.
I understood that the ref has been destroyed by the new component returned by translate function. It's an HOC. I read the Forwarding ref chapter, but I don't understand how to forward ref to the component returned by translate() function.
I have this problem as soon as I use translate from reacti18next and with the result of connect function from redux
I found a solution using onRef props and ComponentDidMount, but some contributors thinks this is an antipattern and I would like to avoid this.
Is there a way to create a wrapper that catch the HOC result of translate() or connect() and add ref to this HOC result ?

React.js setState does not update state even if render method was called

I cannot believe that I cannot update state by setState.
I want to update cardModalOpen state to close the Modal.
I add bind(this) but it still does not work.
(Modal is opened by click Card Component)
However, I did setState({cardModalOpen: false}) by closeModal() function but it is still true even after render method was called.
Can someone please explain what I am doing wrong.
This is my code.
index.js
import React, { Component }from 'react';
import { Button, Card, Image, Header, Modal, Form, Input } from 'semantic-ui-react'
class App extends React.Component {
state = { cardModalOpen:false }
showCardModal() {
this.setState({cardModalOpen:true})
}
closeModal(){
this.setState({cardModalOpen:false})
}
render() {
const messagesDataNew = [];
for (var i = 0; i < 3; i++) {
messagesDataNew.push(
<Card
onClick={() => {
this.showCardModal();
}}
>
<DetailModal
cardModalOpen={this.state.cardModalOpen}
closeModal={this.closeModal}
/>
</Card>
);
}
return <div>{messagesDataNew}</div>;
}
}
DetailModal.js
import React, { Component }from 'react';
import { Button, Card, Image, Header, Modal, Form, Input } from 'semantic-ui-react'
class DetailModal extends Component{
render(){
return(
<Modal open={this.props.cardModalOpen} onClose={()=>{this.props.closeModal()}} >
<Modal.Header>Select a Photo</Modal.Header>
<Modal.Content image>
<Image wrapped size='medium' src='https://react.semantic-ui.com/images/avatar/large/rachel.png' />
<Modal.Description>
<Header>Default Profile Image</Header>
<p>We've found the following gravatar image associated with your e-mail address.</p>
<p>Is it okay to use this photo?</p>
</Modal.Description>
</Modal.Content>
<Button onClick={()=>{this.props.closeModal()}}>Close</Button>
</Modal>
)
}
}
export default DetailModal;
Here is a codesandbox with issue reproduced https://codesandbox.io/s/jjk7nw647y

In codesandbox you shared there is no clickable trigger-element for any of the modals. That's because of you are rendering an empty content of Card.
Here is my changes to your example https://codesandbox.io/s/l97n95n2om
The only difference is line #20 - I added a text Some text so your Card component has valid visible (and clickable) DOM element.

Do not forget bind your state handler functions:
constructor(props){
super(props)
this.showCardModal=this.showCardModal.bind(this)
this.closeModal =this.closeModal.bind(this)
}

React-Redux Infinite loop because of possibly changing state [duplicate]

This question already has answers here:
Why do event handlers need to be references and not invocations?
(2 answers)
Closed 5 years ago.
Good afternoon,
In my class PageList I want to add a function that changes the state on click. However when I insert this function into the a button that doesnt even get clicked the browser starts a never ending loop changing the state of currentpage.
Even though I have read the docs about components this seems strange behaviour. The behaviour accurs when addPage button is clicked.
Thanks in advance!
PageList:
import React, {Component} from 'react';
import {bindActionCreators} from 'redux';
import {connect} from 'react-redux';
import Page from '../components/Page.jsx';
import {addPage} from '../actions/addPage.js'
import {nextPage} from '../actions/nextPage.js'
import RaisedButton from 'material-ui/RaisedButton';
import _ from 'lodash';
class PageList extends Component {
constructor(props){
super(props);
this.state = {
currentpage : 0,
};
}
nextPage(){
this.setState({currentpage: this.state.currentpage+1});
}
renderList() {
if(this.props.item){
return (
<div>
<RaisedButton label="Next Page" onClick={this.nextPage()}></RaisedButton>
<Page key={this.state.currentpage} index={this.state.currentpage}>
{this.props.item.title}
{this.props.item.desc}
</Page>
</div>
);
}else{
return(
<p>No Pages</p>
)
}
}
render() {
return (
<div>
<RaisedButton label="Add new Page" onClick={() => this.props.addPage("Titel Page", "Page Beschrijving")}></RaisedButton>
<ul>
{this.renderList()}
</ul>
</div>
);
}
}
// Get apps state and pass it as props to PageList
// > whenever state changes, the PageList will automatically re-render
function mapStateToProps(state, ownProps) {
return {
pageList: state.pageList,
item: _.find(state.pages, 'id', ownProps.currentpage)
};
}
// Get actions and pass them as props to to PageList
// > now PageList has this.props.selectPage
function matchDispatchToProps(dispatch){
return bindActionCreators({addPage: addPage, nextPage: nextPage}, dispatch);
}
// We don't want to return the plain PageList (component) anymore, we want to return the smart Container
// > PageList is now aware of state and actions
export default connect(mapStateToProps, matchDispatchToProps)(PageList);

You're calling the nextPage function on each render instead of passing it to onClick.
Change onClick={this.nextPage()} with onClick={() => this.nextPage()}

There is a little error:
<RaisedButton label="Next Page" onClick={this.nextPage}>
</RaisedButton>
otherwise this.nextPage() is called right when it is rendered.