How to slide or hide a div with transition in react? - css

Question

I am trying to display a div with the click of a button with slide effect. When something is clicked, it will toggle as shown or invisible with slide effect. I have achieved this so far by doing this.
class App extends Component {
constructor() {
super();
this.state = {
myclass: '',
}
this.divclicked = this.divclicked.bind(this);
}
divclicked() {
if (this.state.myclass === '') {
this.setState({
myclass: 'coolclass'
})
}
else {
this.setState({
myclass: '',
})
}
}
render() {
return (
<div className="App">
<div id="box" onClick={this.divclicked}>
</div>
<div id="seconddiv" className={this.state.myclass}>
<p>help help</p>
<p>help help</p>
<p>help help</p>
<p>help help</p>
<p>help help</p>
</div>
</div>
);
}
}
export default App;
And my CSS
#box {
height: 50px;
width: 50px;
background-color: red
}
#seconddiv.coolclass{
height:300px;
background: purple;
}
#seconddiv {
height: 0px;
transition: 0.5s;
overflow: hidden;
}
So here, when the red box with the id of "box" is clicked, I give the "seconddiv" a className and CSS takes care of hiding the div. The problem is that when I am giving the className coolclass, I do not want to use px but want to use percentage. So currently, it is going from 0px to 300px. But I want it to go from 0px to 100%; How do I achieve this. When I try to put the height of 100% in seconddiv, the slide animation doesn't work.

Answer 1

You need to set your initial height to 0%. You also need to give .App a height of 100% so that it stretches the full height of the window. In this example, I gave it a static height of 1200px, but that should be determined by the body.
class App extends React.Component {
constructor() {
super();
this.state = {
myclass: '',
}
this.divclicked = this.divclicked.bind(this);
}
divclicked() {
if (this.state.myclass === '') {
this.setState({
myclass: 'coolclass'
})
}
else {
this.setState({
myclass: '',
})
}
}
render() {
return (
<div className="App">
<div id="box" onClick={this.divclicked}>
</div>
<div id="seconddiv" className={this.state.myclass}>
<p>help help</p>
<p>help help</p>
<p>help help</p>
<p>help help</p>
<p>help help</p>
</div>
</div>
);
}
}
ReactDOM.render(<App/>,document.getElementById('root'));
#box {
height: 50px;
width: 50px;
background-color: red
}
#seconddiv.coolclass{
max-height:100%;
background: purple;
}
#seconddiv {
max-height: 0%;
transition: 0.5s;
overflow: hidden;
}
.App {
height: 100%;
}
#root {
height: 1200px;
}
<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>
<div id="root"></div>

Answer 2

You can just combine conditional rendering ( x && y ) with some scale animation
Example
const scaleAnimationIn = keyframes`
0% {
transform: scale(0, 1);
animation-timing-function: ease-out;
}
100% {
transform: scale(1, 1);
}
`
const QuestionHeaderPausedText = styled.div`
animation: ${scaleAnimationIn} 1s;
animation-delay: 7s;
animation-fill-mode: both;
`
In the return/render method just:
{isSomeConditionTrue && <QuestionHeaderPausedText>
My text
</QuestionHeaderPausedText>}
This example use Styled Components but the method (scaling) will work with any css solution.