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Using click events on button click

I am new to React and let's suppose we have the following piece of code.
const showDetails = () => {
console.log('Show details')
}
const template = (
<div>
<h1>Vibility Toggle</h1>
<button onClick={showDetails}>Show details</button>
</div>
)
var app = document.getElementById('app')
ReactDOM.render(template, app)
What I want is to change the button's title from Show Details to Hide Details when it is clicked. So I' ve thinking to get the click event inside the function and change the title by using a ternary operator. How to do that?
Thanks
Theo.

you can use the state to handle toggle event in react. I have added a snippet of toggle handler.
import React, { Component } from 'react';
class App extends Component {
state = {
isVisible : true
}
toggleDetails = () => {
this.setState({
isVisible : !this.state.isVisible
});
}
render() {
return (<div>
<h1>Vibility Toggle ({this.state.isVisible ? "is Visible" : "is Not Visisble"})</h1>
<button onClick={this.toggleDetails}>{!this.state.isVisible ? "Show details" : "Hide details"}</button>
</div>)
}
}
export default App;

You can also keep it simple by doing something like:
let show = true;
const showDetails = event => {
show = !show;
event.target.innerHTML = show ? "Show Details" : "Hide Details";
};
const template = (
<div>
<h1>Vibility Toggle</h1>
<button onClick={showDetails}>Show Details</button>
</div>
);
var app = document.getElementById("app");
ReactDOM.render(template, app);
<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="app"></div>

you need to use state in React.please read this documentation for state in React
React State.
here is the sample code to change title using ternary operator in React
import React, { Component } from 'react';
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
showDetails: true
}
}
showDetails = () => {
console.log('Show details')
this.setState({ showDetails: !this.state.showDetails })
}
render() {
return (
<div>
<h1>Vibility Toggle</h1>
<button onClick={() => this.showDetails()}>{this.state.showDetails ? 'Show Details' : 'Hide Details'}</button>
</div>
)
}
}
export default App

Remove element from array with onClick and react

I'm very new to JS and React and coding in general. I'm trying to remove an item from an array using onClick, like so:
const { Component } = React;
class Board extends Component{
constructor(props) {
super(props);
this.state = {
comments: [
'I like Rosie',
'I like you',
'I like bacon',
'lalalala'
],
}
}
removeComment = (e) =>{
var filteredArray = this.state.comments.filter(item => item !== e.target.value)
this.setState({comments: filteredArray});
console.log(e.target.value)
}
eachComment = (text, i) => {
return ( <p id={i} key={i} > comment: {text} {i}</p> )
}
render(){
console.log('render');
return (
<div className="gif-list" onClick={this.removeComment}>
{this.state.comments.map(this.eachComment)}
</div>
);
}
}
ReactDOM.render(
<Board/>,
document.querySelector('#mount'));
<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="mount"><div>
Not much is happening though. My console.log(e.target.value) comes back as undefined. What am I doing wrong?
I have tried looking at other answers but implementing (to me) abstract solutions to other similar problems is not working for me.
Thanks in advance, and apologies for such a simple question.

The div you have the event handler on does not have a value attribute. But even if it did I don't think it will do what you want.
You'll need to change your code a bit in order to get it working like you want:
class Board extends React.Component{
constructor(props) {
super(props);
this.state = {
comments: [
'I like Rosie',
'I like you',
'I like bacon',
'lalalala'
],
}
}
removeComment = (e) =>{
// Check the index in the filter to see if it should be kept or removed
var filteredArray = this.state.comments.filter((item, i) => i != e.target.id)
this.setState({comments: filteredArray});
console.log(e.target.id)
}
eachComment = (text, i) => {
// Move the event handler to be on each item
return ( <p id={i} key={i} onClick={this.removeComment}> comment: {text} {i}</p> )
}
render(){
return (
<div className="gif-list">
{this.state.comments.map(this.eachComment)}
</div>
);
}
}
ReactDOM.render(<Board />, 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" />
You'll notice the important changes are:
Give the remove handler to each mapped element
Use an attribute from the event target that actually exists and can be used to determine which element should be removed.

For this one you need to specifically pass in the param when you bind the onClick function
return (
<div className="gif-list" onClick={(e)=>this.removeComment(e)}>
{this.state.comments.map(this.eachComment)}
</div>
);

How to get values/properties from a react-bootstrap checkbox?

I'm trying to use the react-bootstrap checkbox (https://react-bootstrap.github.io/components.html#forms-controls) and I need to fire an event when it changes state. It would also be great to be able to programatically un/check it and/or tell if it is checked. Unfortunately when the code is transpiled and rendered it wraps the input in a div.
How can I find this in the dom and manipulate it?
My code looks similar to this:
import React, { PropTypes } from 'react';
import { Checkbox } from 'react-bootstrap';
const EditItem = (props) => {
return (
<div>
<Checkbox style={{ marginLeft: '15px' }} >{props.itemLable}</Checkbox>
</div>
);
};
export default EditItem;
And the browser renders this:
...
<div class="checkbox" style="margin-left: 15px;">
<label>
<input type="checkbox">
</label>
</div>
...
I see the inputRef prop in the documentation but I can't find any examples of this or get it to work myself.

There are two ways: The React way and the not-so-React way.
The React way is to set the child component's state by passing it props and respond to changes in its state by attaching event handlers. In the case of Checkbox, that means setting the checked and onChange props.
Note in the below example how the parent component (App) keeps track of the Checkbox's state and can both set it with this.setState and query it with this.state.checkboxChecked.
const { Checkbox, Button } = ReactBootstrap;
class App extends React.Component {
constructor() {
super();
this.state = { checkboxChecked: false };
this.handleChange = this.handleChange.bind(this);
this.handleIsItChecked = this.handleIsItChecked.bind(this);
this.handleToggle = this.handleToggle.bind(this);
}
render() {
return (
<div>
<Checkbox
checked={this.state.checkboxChecked}
onChange={this.handleChange} />
<Button type="button" onClick={this.handleToggle}>Toggle</Button>
<Button type="button" onClick={this.handleIsItChecked}>Is it checked?</Button>
</div>
);
}
handleChange(evt) {
this.setState({ checkboxChecked: evt.target.checked });
}
handleIsItChecked() {
console.log(this.state.checkboxChecked ? 'Yes' : 'No');
}
handleToggle() {
this.setState({ checkboxChecked: !this.state.checkboxChecked });
}
}
ReactDOM.render(<App/>, document.querySelector('div'));
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/latest/css/bootstrap.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/react-bootstrap/0.30.8/react-bootstrap.min.js"></script>
<div></div>
The not-so-React way is to get a reference to the rendered DOM element and access its checked property directly. I don't recommend this, because it necessarily pollutes your lovely functional React code with icky imperative code. Nevertheless, with React-Bootstrap you can do it by setting the inputRef prop, as in the below example:
const { Checkbox, Button } = ReactBootstrap;
class App extends React.Component {
constructor() {
super();
this.handleIsItChecked = this.handleIsItChecked.bind(this);
this.handleToggle = this.handleToggle.bind(this);
}
render() {
return (
<div>
<Checkbox
onChange={this.handleChange}
inputRef={ref => this.myCheckbox = ref} />
<Button type="button" onClick={this.handleToggle}>Toggle</Button>
<Button type="button" onClick={this.handleIsItChecked}>Is it checked?</Button>
</div>
);
}
handleIsItChecked() {
console.log(this.myCheckbox.checked ? 'Yes' : 'No');
}
handleToggle() {
this.myCheckbox.checked = !this.myCheckbox.checked;
}
}
ReactDOM.render(<App/>, document.querySelector('div'));
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/latest/css/bootstrap.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/react-bootstrap/0.30.8/react-bootstrap.min.js"></script>
<div></div>

Thanks for the above answers. I generalized the above slightly for use when you have more than one checkbox in a given component:
constructor() {
super();
this.state = { YourInputName: false };
this.handleCheckboxChange = this.handleCheckboxChange.bind(this);
}
render() {
return (
<div>
<Checkbox
name="YourInputName"
onChange={this.handleCheckboxChange} />
</div>
);
}
handleCheckboxChange(event) {
const target = event.target
const checked = target.checked
const name = target.name
this.setState({
[name]: checked,
});
}

Have you tried setting an onChange property to your checkbox?
handleChange(event) {
this.setState(*set checkbox state here*);
}
<Checkbox onChange={this.handleChange}></Checkbox>

change scrollTop in reactjs

I just learn react, and want to achieve a function :
both A,B are components, if A scroll, then B scroll
The following is my code
<A onScroll="handleScroll"></A>
//what i write now
handleScroll: function(event){
var target = event.nativeEvent.target;
//do something to change scrollTop value
target.scrollTop += 1;
// it looks the same as not use react
document.getElementById(B).scrollTop = target.scrollTop;
}
but actually I want my code like this
//what i want
<A scrollTop={this.props.scrollSeed}></A>
<B scrollTop={this.props.scrollSeed}></B>
//...
handleScroll(){
this.setState({scrollSeed: ++this.state.scrollSeed})
}
it is similar to input
<input value="this.props.value"/>
<input value="this.props.value"/>
<input ref='c' onChange={handleChange}>
//...
handleChange: function() {
// enter some code in c and then render in a and b automatically
}
In other words, I want some attribute, like scrollTop(different
form <input value={}> ,because <A scrollTop={}> doesn't work) ,is bind with some state, so that I can just use setState, and they will update by themselves.
I googled before but can't find the answser. I hope that my poor English won't confuse you.

There are a number of patterns to achieve this. This sample is what I came up with to get you up and going.
First create a component class which has an oversize element for scroll effect. When dragging the scroll bar, this component calls its handleScroll React property to notify its parent component, with the value of scrollTop.
var Elem = React.createClass({
render() {
return (
<div ref="elem"
onScroll={ this.onScroll }
style={{ width: "100px", height: "100px", overflow: "scroll" }}>
<div style={{ width: "100%", height: "200%" }}>Hello!</div>
</div>
);
},
componentDidUpdate() {
this.refs.elem.scrollTop = this.props.scrollTop;
},
onScroll() {
this.props.handleScroll( this.refs.elem.scrollTop );
}
});
The parent component, aka wrapper, keeps the scroll top value in its state. Its handleScroll is passed to the child components as callback. Any scroll on the child elements triggers the callback, sets the state, results in a redraw, and updates the child component.
var Wrapper = React.createClass({
getInitialState() {
return {
scrollTop: 0
}
},
render() {
return (
<div>
<Elem scrollTop={ this.state.scrollTop } handleScroll={ this.handleScroll } />
<Elem scrollTop={ this.state.scrollTop } handleScroll={ this.handleScroll } />
</div>
);
},
handleScroll( scrollTop ) {
this.setState({ scrollTop });
}
});
And render the wrapper, presuming an existing <div id="container"></div>.
ReactDOM.render(
<Wrapper />,
document.getElementById('container')
);

2019's answer
First, the fix:
const resetScrollEffect = ({ element }) => {
element.current.getScrollableNode().children[0].scrollTop = 0
}
const Table = props => {
const tableRef = useRef(null)
useEffect(() => resetScrollEffect({ element: tableRef }), [])
return (
<Component>
<FlatList
ref={someRef}
/>
</Component>
)
}
Second, a little explanation:
Idk what is your reason why you got here but I have used flex-direction: column-reverse for my FlatList (it's a list of elements). And I need this property for z-index purposes. However, browsers set their scroll position to the end for such elements (tables, chats, etc.) - this may be useful but I don't need that in my case.
Also, example is shown using React Hooks, but you can use older more traditional way of defining refs

this.refs is deprecated. use reactjs.org/docs/refs-and-the-dom.html#creating-refs
import React from 'react';
class SomeComponent extends React.Component {
constructor(props) {
super(props);
this.resultsDiv = React.createRef();
}
someFunction(){
this.resultsDiv.current.scrollIntoView({behavior: 'smooth'});
// alternative:
// this.resultsDiv.current.scrollTop = 0;
}
render() {
return (
<div ref={this.resultsDiv} />
);
}
}
export default SomeComponent;

Here's an updated version of Season's answer, including a runnable snippet. It uses the recommended method for creating refs.
class Editor extends React.Component {
constructor(props) {
super(props);
this.content = React.createRef();
this.handleScroll = this.handleScroll.bind(this);
}
componentDidUpdate() {
this.content.current.scrollTop = this.props.scrollTop;
}
handleScroll() {
this.props.onScroll( this.content.current.scrollTop );
}
render() {
let text = 'a\n\nb\n\nc\n\nd\n\ne\n\nf\n\ng';
return <textarea
ref={this.content}
value={text}
rows="10"
cols="30"
onScroll={this.handleScroll}/>;
}
}
class App extends React.Component {
constructor(props) {
super(props);
this.state = {scrollTop: 0};
this.handleScroll = this.handleScroll.bind(this);
}
handleScroll(scrollTop) {
this.setState({scrollTop: scrollTop});
}
render() {
return <table><tbody>
<tr><th>Foo</th><th>Bar</th></tr>
<tr>
<td><Editor
scrollTop={this.state.scrollTop}
onScroll={this.handleScroll}/></td>
<td><Editor
scrollTop={this.state.scrollTop}
onScroll={this.handleScroll}/></td>
</tr>
</tbody></table>;
}
}
ReactDOM.render(
<App/>,
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>

Show or hide element in React

I am messing around with React.js for the first time and cannot find a way to show or hide something on a page via click event. I am not loading any other library to the page, so I am looking for some native way using the React library. This is what I have so far. I would like to show the results div when the click event fires.
var Search= React.createClass({
handleClick: function (event) {
console.log(this.prop);
},
render: function () {
return (
<div className="date-range">
<input type="submit" value="Search" onClick={this.handleClick} />
</div>
);
}
});
var Results = React.createClass({
render: function () {
return (
<div id="results" className="search-results">
Some Results
</div>
);
}
});
React.renderComponent(<Search /> , document.body);

React circa 2020
In the onClick callback, call the state hook's setter function to update the state and re-render:
const Search = () => {
const [showResults, setShowResults] = React.useState(false)
const onClick = () => setShowResults(true)
return (
<div>
<input type="submit" value="Search" onClick={onClick} />
{ showResults ? <Results /> : null }
</div>
)
}
const Results = () => (
<div id="results" className="search-results">
Some Results
</div>
)
ReactDOM.render(<Search />, document.querySelector("#container"))
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.13.1/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.13.1/umd/react-dom.production.min.js"></script>
<div id="container">
<!-- This element's contents will be replaced with your component. -->
</div>
JSFiddle
React circa 2014
The key is to update the state of the component in the click handler using setState. When the state changes get applied, the render method gets called again with the new state:
var Search = React.createClass({
getInitialState: function() {
return { showResults: false };
},
onClick: function() {
this.setState({ showResults: true });
},
render: function() {
return (
<div>
<input type="submit" value="Search" onClick={this.onClick} />
{ this.state.showResults ? <Results /> : null }
</div>
);
}
});
var Results = React.createClass({
render: function() {
return (
<div id="results" className="search-results">
Some Results
</div>
);
}
});
ReactDOM.render( <Search /> , document.getElementById('container'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.6.2/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/15.6.2/react-dom.min.js"></script>
<div id="container">
<!-- This element's contents will be replaced with your component. -->
</div>
JSFiddle

<style type="text/css">
.hidden { display:none; }
</style>
const Example = props =>
<div className={props.shouldHide? 'hidden' : undefined}>Hello</div>

Here is an alternative syntax for the ternary operator:
{ this.state.showMyComponent ? <MyComponent /> : null }
is equivalent to:
{ this.state.showMyComponent && <MyComponent /> }
Learn why
Also alternative syntax with display: 'none';
<MyComponent style={this.state.showMyComponent ? {} : { display: 'none' }} />
However, if you overuse display: 'none', this leads to DOM pollution and ultimately slows down your application.

Here is my approach.
import React, { useState } from 'react';
function ToggleBox({ title, children }) {
const [isOpened, setIsOpened] = useState(false);
function toggle() {
setIsOpened(wasOpened => !wasOpened);
}
return (
<div className="box">
<div className="boxTitle" onClick={toggle}>
{title}
</div>
{isOpened && (
<div className="boxContent">
{children}
</div>
)}
</div>
);
}
In code above, to achieve this, I'm using code like:
{opened && <SomeElement />}
That will render SomeElement only if opened is true. It works because of the way how JavaScript resolve logical conditions:
true && true && 2; // will output 2
true && false && 2; // will output false
true && 'some string'; // will output 'some string'
opened && <SomeElement />; // will output SomeElement if `opened` is true, will output false otherwise (and false will be ignored by react during rendering)
// be careful with 'falsy' values eg
const someValue = [];
someValue.length && <SomeElement /> // will output 0, which will be rednered by react
// it'll be better to:
someValue.length > 0 && <SomeElement /> // will render nothing as we cast the value to boolean
Reasons for using this approach instead of CSS 'display: none';
While it might be 'cheaper' to hide an element with CSS - in such case 'hidden' element is still 'alive' in react world (which might make it actually way more expensive)
it means that if props of the parent element (eg. <TabView>) will change - even if you see only one tab, all 5 tabs will get re-rendered
the hidden element might still have some lifecycle methods running - eg. it might fetch some data from the server after every update even tho it's not visible
the hidden element might crash the app if it'll receive incorrect data. It might happen as you can 'forget' about invisible nodes when updating the state
you might by mistake set wrong 'display' style when making element visible - eg. some div is 'display: flex' by default, but you'll set 'display: block' by mistake with display: invisible ? 'block' : 'none' which might break the layout
using someBoolean && <SomeNode /> is very simple to understand and reason about, especially if your logic related to displaying something or not gets complex
in many cases, you want to 'reset' element state when it re-appears. eg. you might have a slider that you want to set to initial position every time it's shown. (if that's desired behavior to keep previous element state, even if it's hidden, which IMO is rare - I'd indeed consider using CSS if remembering this state in a different way would be complicated)

with the newest version react 0.11 you can also just return null to have no content rendered.
Rendering to null

This is a nice way to make use of the virtual DOM:
class Toggle extends React.Component {
state = {
show: true,
}
toggle = () => this.setState((currentState) => ({show: !currentState.show}));
render() {
return (
<div>
<button onClick={this.toggle}>
toggle: {this.state.show ? 'show' : 'hide'}
</button>
{this.state.show && <div>Hi there</div>}
</div>
);
}
}
Example here
Using React hooks:
const Toggle = () => {
const [show, toggleShow] = React.useState(true);
return (
<div>
<button
onClick={() => toggleShow(!show)}
>
toggle: {show ? 'show' : 'hide'}
</button>
{show && <div>Hi there</div>}
</div>
)
}
Example here

I created a small component that handles this for you: react-toggle-display
It sets the style attribute to display: none !important based on the hide or show props.
Example usage:
var ToggleDisplay = require('react-toggle-display');
var Search = React.createClass({
getInitialState: function() {
return { showResults: false };
},
onClick: function() {
this.setState({ showResults: true });
},
render: function() {
return (
<div>
<input type="submit" value="Search" onClick={this.onClick} />
<ToggleDisplay show={this.state.showResults}>
<Results />
</ToggleDisplay>
</div>
);
}
});
var Results = React.createClass({
render: function() {
return (
<div id="results" className="search-results">
Some Results
</div>
);
}
});
React.renderComponent(<Search />, document.body);

There are several great answers already, but I don't think they've been explained very well and several of the methods given contain some gotchas that might trip people up. So I'm going to go over the three main ways (plus one off-topic option) to do this and explain the pros and cons. I'm mostly writing this because Option 1 was recommended a lot and there's a lot of potential issues with that option if not used correctly.
Option 1: Conditional Rendering in the parent.
I don't like this method unless you're only going to render the component one time and leave it there. The issue is it will cause react to create the component from scratch every time you toggle the visibility.
Here's the example. LogoutButton or LoginButton are being conditionally rendered in the parent LoginControl. If you run this you'll notice the constructor is getting called on each button click. https://codepen.io/Kelnor/pen/LzPdpN?editors=1111
class LoginControl extends React.Component {
constructor(props) {
super(props);
this.handleLoginClick = this.handleLoginClick.bind(this);
this.handleLogoutClick = this.handleLogoutClick.bind(this);
this.state = {isLoggedIn: false};
}
handleLoginClick() {
this.setState({isLoggedIn: true});
}
handleLogoutClick() {
this.setState({isLoggedIn: false});
}
render() {
const isLoggedIn = this.state.isLoggedIn;
let button = null;
if (isLoggedIn) {
button = <LogoutButton onClick={this.handleLogoutClick} />;
} else {
button = <LoginButton onClick={this.handleLoginClick} />;
}
return (
<div>
<Greeting isLoggedIn={isLoggedIn} />
{button}
</div>
);
}
}
class LogoutButton extends React.Component{
constructor(props, context){
super(props, context)
console.log('created logout button');
}
render(){
return (
<button onClick={this.props.onClick}>
Logout
</button>
);
}
}
class LoginButton extends React.Component{
constructor(props, context){
super(props, context)
console.log('created login button');
}
render(){
return (
<button onClick={this.props.onClick}>
Login
</button>
);
}
}
function UserGreeting(props) {
return <h1>Welcome back!</h1>;
}
function GuestGreeting(props) {
return <h1>Please sign up.</h1>;
}
function Greeting(props) {
const isLoggedIn = props.isLoggedIn;
if (isLoggedIn) {
return <UserGreeting />;
}
return <GuestGreeting />;
}
ReactDOM.render(
<LoginControl />,
document.getElementById('root')
);
Now React is pretty quick at creating components from scratch. However, it still has to call your code when creating it. So if your constructor, componentDidMount, render, etc code is expensive, then it'll significantly slow down showing the component. It also means you cannot use this with stateful components where you want the state to be preserved when hidden (and restored when displayed.) The one advantage is that the hidden component isn't created at all until it's selected. So hidden components won't delay your initial page load. There may also be cases where you WANT a stateful component to reset when toggled. In which case this is your best option.
Option 2: Conditional Rendering in the child
This creates both components once. Then short circuits the rest of the render code if the component is hidden. You can also short circuit other logic in other methods using the visible prop. Notice the console.log in the codepen page. https://codepen.io/Kelnor/pen/YrKaWZ?editors=0011
class LoginControl extends React.Component {
constructor(props) {
super(props);
this.handleLoginClick = this.handleLoginClick.bind(this);
this.handleLogoutClick = this.handleLogoutClick.bind(this);
this.state = {isLoggedIn: false};
}
handleLoginClick() {
this.setState({isLoggedIn: true});
}
handleLogoutClick() {
this.setState({isLoggedIn: false});
}
render() {
const isLoggedIn = this.state.isLoggedIn;
return (
<div>
<Greeting isLoggedIn={isLoggedIn} />
<LoginButton isLoggedIn={isLoggedIn} onClick={this.handleLoginClick}/>
<LogoutButton isLoggedIn={isLoggedIn} onClick={this.handleLogoutClick}/>
</div>
);
}
}
class LogoutButton extends React.Component{
constructor(props, context){
super(props, context)
console.log('created logout button');
}
render(){
if(!this.props.isLoggedIn){
return null;
}
return (
<button onClick={this.props.onClick}>
Logout
</button>
);
}
}
class LoginButton extends React.Component{
constructor(props, context){
super(props, context)
console.log('created login button');
}
render(){
if(this.props.isLoggedIn){
return null;
}
return (
<button onClick={this.props.onClick}>
Login
</button>
);
}
}
function UserGreeting(props) {
return <h1>Welcome back!</h1>;
}
function GuestGreeting(props) {
return <h1>Please sign up.</h1>;
}
function Greeting(props) {
const isLoggedIn = props.isLoggedIn;
if (isLoggedIn) {
return <UserGreeting />;
}
return <GuestGreeting />;
}
ReactDOM.render(
<LoginControl />,
document.getElementById('root')
);
Now, if the initialization logic is quick and the children are stateless, then you won't see a difference in performance or functionality. However, why make React create a brand new component every toggle anyway? If the initialization is expensive however, Option 1 will run it every time you toggle a component which will slow the page down when switching. Option 2 will run all of the component's inits on first page load. Slowing down that first load. Should note again. If you're just showing the component one time based on a condition and not toggling it, or you want it to reset when toggledm, then Option 1 is fine and probably the best option.
If slow page load is a problem however, it means you've got expensive code in a lifecycle method and that's generally not a good idea. You can, and probably should, solve the slow page load by moving the expensive code out of the lifecycle methods. Move it to an async function that's kicked off by ComponentDidMount and have the callback put it in a state variable with setState(). If the state variable is null and the component is visible then have the render function return a placeholder. Otherwise render the data. That way the page will load quickly and populate the tabs as they load. You can also move the logic into the parent and push the results to the children as props. That way you can prioritize which tabs get loaded first. Or cache the results and only run the logic the first time a component is shown.
Option 3: Class Hiding
Class hiding is probably the easiest to implement. As mentioned you just create a CSS class with display: none and assign the class based on prop. The downside is the entire code of every hidden component is called and all hidden components are attached to the DOM. (Option 1 doesn't create the hidden components at all. And Option 2 short circuits unnecessary code when the component is hidden and removes the component from the DOM completely.) It appears this is faster at toggling visibility according some tests done by commenters on other answers but I can't speak to that.
Option 4: One component but change Props. Or maybe no component at all and cache HTML.
This one won't work for every application and it's off topic because it's not about hiding components, but it might be a better solution for some use cases than hiding. Let's say you have tabs. It might be possible to write one React Component and just use the props to change what's displayed in the tab. You could also save the JSX to state variables and use a prop to decide which JSX to return in the render function. If the JSX has to be generated then do it and cache it in the parent and send the correct one as a prop. Or generate in the child and cache it in the child's state and use props to select the active one.

You set a boolean value in the state (e.g. 'show)', and then do:
var style = {};
if (!this.state.show) {
style.display = 'none'
}
return <div style={style}>...</div>

A simple method to show/hide elements in React using Hooks
const [showText, setShowText] = useState(false);
Now, let's add some logic to our render method:
{showText && <div>This text will show!</div>}
And
onClick={() => setShowText(!showText)}
Good job.

I was able to use css property "hidden". Don't know about possible drawbacks.
export default function App() {
const [hidden, setHidden] = useState(false);
return (
<div>
<button onClick={() => setHidden(!hidden)}>HIDE</button>
<div hidden={hidden}>hidden component</div>
</div>
);
}

Best practice is below according to the documentation:
{this.state.showFooter && <Footer />}
Render the element only when the state is valid.

Simple hide/show example with React Hooks: (srry about no fiddle)
const Example = () => {
const [show, setShow] = useState(false);
return (
<div>
<p>Show state: {show}</p>
{show ? (
<p>You can see me!</p>
) : null}
<button onClick={() => setShow(!show)}>
</div>
);
};
export default Example;

class FormPage extends React.Component{
constructor(props){
super(props);
this.state = {
hidediv: false
}
}
handleClick = (){
this.setState({
hidediv: true
});
}
render(){
return(
<div>
<div className="date-range" hidden = {this.state.hidediv}>
<input type="submit" value="Search" onClick={this.handleClick} />
</div>
<div id="results" className="search-results" hidden = {!this.state.hidediv}>
Some Results
</div>
</div>
);
}
}

I start with this statement from the React team:
In React, you can create distinct components that encapsulate behaviour
you need. Then, you can render only some of them, depending on the
state of your application.
Conditional rendering in React works the same way conditions work in
JavaScript. Use JavaScript operators like if or the conditional
operator to create elements representing the current state, and let
React update the UI to match them.
You basically need to show the component when the button gets clicked, you can do it two ways, using pure React or using CSS, using pure React way, you can do something like below code in your case, so in the first run, results are not showing as hideResults is true, but by clicking on the button, state gonna change and hideResults is false and the component get rendered again with the new value conditions, this is very common use of changing component view in React...
var Search = React.createClass({
getInitialState: function() {
return { hideResults: true };
},
handleClick: function() {
this.setState({ hideResults: false });
},
render: function() {
return (
<div>
<input type="submit" value="Search" onClick={this.handleClick} />
{ !this.state.hideResults && <Results /> }
</div> );
}
});
var Results = React.createClass({
render: function() {
return (
<div id="results" className="search-results">
Some Results
</div>);
}
});
ReactDOM.render(<Search />, document.body);
If you want to do further study in conditional rendering in React, have a look here.

class Toggle extends React.Component {
state = {
show: true,
}
render() {
const {show} = this.state;
return (
<div>
<button onClick={()=> this.setState({show: !show })}>
toggle: {show ? 'show' : 'hide'}
</button>
{show && <div>Hi there</div>}
</div>
);
}
}

If you would like to see how to TOGGLE the display of a component checkout this fiddle.
http://jsfiddle.net/mnoster/kb3gN/16387/
var Search = React.createClass({
getInitialState: function() {
return {
shouldHide:false
};
},
onClick: function() {
console.log("onclick");
if(!this.state.shouldHide){
this.setState({
shouldHide: true
})
}else{
this.setState({
shouldHide: false
})
}
},
render: function() {
return (
<div>
<button onClick={this.onClick}>click me</button>
<p className={this.state.shouldHide ? 'hidden' : ''} >yoyoyoyoyo</p>
</div>
);
}
});
ReactDOM.render( <Search /> , document.getElementById('container'));

Use ref and manipulate CSS
One way could be to use React's ref and manipulate CSS class using the browser's API. Its benefit is to avoid rerendering in React if the sole purpose is to hide/show some DOM element on the click of a button.
// Parent.jsx
import React, { Component } from 'react'
export default class Parent extends Component {
constructor () {
this.childContainer = React.createRef()
}
toggleChild = () => {
this.childContainer.current.classList.toggle('hidden')
}
render () {
return (
...
<button onClick={this.toggleChild}>Toggle Child</button>
<div ref={this.childContainer}>
<SomeChildComponent/>
</div>
...
);
}
}
// styles.css
.hidden {
display: none;
}
PS Correct me if I am wrong. :)

In some cases higher order component might be useful:
Create higher order component:
export var HidableComponent = (ComposedComponent) => class extends React.Component {
render() {
if ((this.props.shouldHide!=null && this.props.shouldHide()) || this.props.hidden)
return null;
return <ComposedComponent {...this.props} />;
}
};
Extend your own component:
export const MyComp= HidableComponent(MyCompBasic);
Then you can use it like this:
<MyComp hidden={true} ... />
<MyComp shouldHide={this.props.useSomeFunctionHere} ... />
This reduces a bit boilerplate and enforces sticking to naming conventions, however please be aware of that MyComp will still be instantiated - the way to omit is was mentioned earlier:
{ !hidden && <MyComp ... /> }

If you use bootstrap 4, you can hide element that way
className={this.state.hideElement ? "invisible" : "visible"}

Use rc-if-else module
npm install --save rc-if-else
import React from 'react';
import { If } from 'rc-if-else';
class App extends React.Component {
render() {
return (
<If condition={this.props.showResult}>
Some Results
</If>
);
}
}

Use this lean and short syntax:
{ this.state.show && <MyCustomComponent /> }

Here comes the simple, effective and best solution with a Classless React Component for show/hide the elements. Use of React-Hooks which is available in the latest create-react-app project that uses React 16
import React, {useState} from 'react';
function RenderPara(){
const [showDetail,setShowDetail] = useState(false);
const handleToggle = () => setShowDetail(!showDetail);
return (
<React.Fragment>
<h3>
Hiding some stuffs
</h3>
<button onClick={handleToggle}>Toggle View</button>
{showDetail && <p>
There are lot of other stuffs too
</p>}
</React.Fragment>)
}
export default RenderPara;
Happy Coding :)

//use ternary condition
{ this.state.yourState ? <MyComponent /> : null }
{ this.state.yourState && <MyComponent /> }
{ this.state.yourState == 'string' ? <MyComponent /> : ''}
{ this.state.yourState == 'string' && <MyComponent /> }
//Normal condition
if(this.state.yourState){
return <MyComponent />
}else{
return null;
}
<button onClick={()=>this.setState({yourState: !this.props.yourState}>Toggle View</button>

Just figure out a new and magic way with using(useReducer) for functional components
const [state, handleChangeState] = useReducer((state) => !state, false);
change state

This can also be achieved like this (very easy way)
class app extends Component {
state = {
show: false
};
toggle= () => {
var res = this.state.show;
this.setState({ show: !res });
};
render() {
return(
<button onClick={ this.toggle }> Toggle </button>
{
this.state.show ? (<div> HELLO </div>) : null
}
);
}

this example shows how you can switch between components by using a toggle which switches after every 1sec
import React ,{Fragment,Component} from "react";
import ReactDOM from "react-dom";
import "./styles.css";
const Component1 = () =>(
<div>
<img
src="https://i.pinimg.com/originals/58/df/1d/58df1d8bf372ade04781b8d4b2549ee6.jpg" />
</div>
)
const Component2 = () => {
return (
<div>
<img
src="http://www.chinabuddhismencyclopedia.com/en/images/thumb/2/2e/12ccse.jpg/250px-
12ccse.jpg" />
</div>
)
}
class App extends Component {
constructor(props) {
super(props);
this.state = {
toggleFlag:false
}
}
timer=()=> {
this.setState({toggleFlag:!this.state.toggleFlag})
}
componentDidMount() {
setInterval(this.timer, 1000);
}
render(){
let { toggleFlag} = this.state
return (
<Fragment>
{toggleFlag ? <Component1 /> : <Component2 />}
</Fragment>
)
}
}
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

The application of states and effects has and must be encapsulated in the same component, for this reason, there is nothing better than creating a custom component as a hook to solve in this case whether to make particular blocks or elements visible or invisible.
// hooks/useOnScreen.js
import { useState, useEffect } from "react"
const useOnScreen = (ref, rootMargin = "0px") => {
const [isVisible, setIsVisible] = useState(false)
useEffect(() => {
const observer = new IntersectionObserver(
([entry]) => {
setIsVisible(entry.isIntersecting)
},
{
rootMargin
}
);
const currentElement = ref?.current
if (currentElement) {
observer.observe(currentElement)
}
return () => {
observer.unobserve(currentElement)
}
}, [])
return isVisible
}
export default useOnScreen
Then the custom hook is embedded inside the component
import React, { useRef } from "react";
import useOnScreen from "hooks/useOnScreen";
const MyPage = () => {
const ref = useRef(null)
const isVisible = useOnScreen(ref)
const onClick = () => {
console.log("isVisible", isVisible)
}
return (
<div ref={ref}>
<p isVisible={isVisible}>
Something is visible
</p>
<a
href="#"
onClick={(e) => {
e.preventDefault();
onClick(onClick)
}}
>
Review
</a>
</div>
)
}
export default MyPage
The ref variable, controlled by the useRef hook, allows us to capture the location in the DOM of the block that we want to control, then the isVisible variable, controlled by the useOnScreen hook, allows us to make the inside the block I signal by the useRef hook.
I believe that this implementation of the useState, useEfect, and useRef hooks allows you to avoid component rendering by separating them using custom hooks.
Hoping that this knowledge will be of use to you.

It is very simple to hide and show the elements in react.
There are multiple ways but I will show you two.
Way 1:
const [isVisible, setVisible] = useState(false)
let onHideShowClick = () =>{
setVisible(!isVisible)
}
return (<div>
<Button onClick={onHideShowClick} >Hide/Show</Button>
{(isVisible) ? <p>Hello World</p> : ""}
</div>)
Way 2:
const [isVisible, setVisible] = useState(false)
let onHideShowClick = () =>{
setVisible(!isVisible)
}
return (<div>
<Button onClick={onHideShowClick} >Hide/Show</Button>
<p style={{display: (isVisible) ? 'block' : 'none'}}>Hello World</p>
</div>)
It is just working like if and else.
In Way one, it will remove and re-render elements in Dom.
In the Second way you are just displaying elements as false or true.
Thank you.

You've to do the small change in the code for continuously hiding and showing
const onClick = () => {setShowResults(!showResults}
Problem will be solved
const Search = () => {
const [showResults, setShowResults] = React.useState(false)
const onClick = () => setShowResults(true)
const onClick = () => {setShowResults(!showResults}
return (
<div>
<input type="submit" value="Search" onClick={onClick} />
{ showResults ? <Results /> : null }
</div>
)
}
const Results = () => (
<div id="results" className="search-results">
Some Results
</div>
)
ReactDOM.render(<Search />, document.querySelector("#container"))
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.13.1/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.13.1/umd/react-dom.production.min.js"></script>
<div id="container">
<!-- This element's contents will be replaced with your component. -->
</div>
```