Im working on something with React and mobx.
I created an ImageCarousel Component where I show the image that was clicked.
I have a previous and a next buttons(which are themselves a Component), to move between images.
I tried to wrap those actions (prev and next) with
lodash debounce
prevCarousel
nextCarousel
debounceAction
debounceAction
lodash debounce
onClick
debounceAction(fn, wait)
debounceAction
class GalleryStore {
// Observables
@observable images = [
// ....images
];
@observable carouselleButtons= {
next: "fa fa-chevron-right",
back: "fa fa-chevron-left"
}
@observable selectedImageIndex = null;
@observable hideCarousel = true;
@observable onTransition = false;
// Actions
selectImage = (index) =>{
this.selectedImageIndex = index;
}
toggleCarousel = () =>{
this.hideCarousel = !this.hideCarousel;
}
carouselNext = () => {
if(this.selectedImageIndex == this.images.length - 1) {
return;
}
this.onTransition = true;
setTimeout(() => {
this.selectedImageIndex = this.selectedImageIndex + 1;
this.onTransition = false;
},500)
}
carouselPrev = () => {
if(this.selectedImageIndex == 0) {
console.log('start of the collection');
return;
}
this.onTransition = true;
setTimeout(() => {
this.selectedImageIndex = this.selectedImageIndex - 1;
this.onTransition = false;
}, 500)
}
debounceAction = (fn, wait) => {
//lodash's debounce
return debounce(fn, wait);
}
// React's
import React from 'react';
// Styles
import CarouselButtonStyle from './carouselButtonStyle';
// CarouselButton Component
export default class CarouselButton extends React.Component {
debounce = (e) =>{
const { debounceAction } = this.props;
// -----> HERE I CALL DEBOUNCE ! <---------
e.stopPropagation();
debounceAction(this.buttonHandler, 400);
}
buttonHandler = (e) => {
const {limit, index, action, debounceAction} = this.props;
if(index == limit) return;
else action();
}
render(){
const {limit, index, icon, action, debounceAction} = this.props;
return(
<CarouselButtonStyle
onClick={(e) => {this.debounce(e)}}
className={ index == limit ? 'end-of-collection' : '' } >
<i className={icon} aria-hidden="true" />
</CarouselButtonStyle>
);
}
}
// React's
import React from 'react';
// Mobx-react's
import { observer, inject } from 'mobx-react';
// Styles
import ImageCarouselStyle from './imageCarouselStyle';
// Components
import ImgContainer from './imgContainer/imgContainer';
import CarouselButton from './carouselButton/carouselButton';
// ImageCarousel Component
@inject('galleryStore')
@observer
export default class ImageCarousel extends React.Component {
closeCarousel = () => {
this.props.galleryStore.toggleCarousel();
}
onKeyDown = (e) => {
const { keyCode } = e;
if(keyCode ===27) this.onEscHandler();
else if (keyCode == 37) this.onLeftArrow();
else if (keyCode == 39) this.onRightArrow();
else return;
}
onLeftArrow = () => { this.props.galleryStore.carouselPrev() }
onRightArrow = () => { this.props.galleryStore.carouselNext() }
onEscHandler = () => { this.closeCarousel() }
componentDidMount(){
document.addEventListener('keydown', this.onKeyDown, false);
}
render(){
return(
<ImageCarouselStyle
hidden={this.props.galleryStore.hideCarousel}
onClick={this.closeCarousel} >
<CarouselButton action={'prev'}
icon={this.props.galleryStore.carouselleButtons.back}
action={this.props.galleryStore.carouselPrev}
limit={0}
index={this.props.galleryStore.selectedImageIndex}
debounceAction={this.props.galleryStore.debounceAction} />
<ImgContainer
images={this.props.galleryStore.images}
imgIndex={this.props.galleryStore.selectedImageIndex}
onTransition={this.props.galleryStore.onTransition}/>
<CarouselButton action={'next'}
icon={this.props.galleryStore.carouselleButtons.next}
action={this.props.galleryStore.carouselNext}
limit={this.props.galleryStore.amountOfImages}
index={this.props.galleryStore.selectedImageIndex}
debounceAction={this.props.galleryStore.debounceAction} />
</ImageCarouselStyle>
);
}
}
The issue is that you have to return debounceAction
from CarouselButton
's debounce
method.
debounce = (e) =>{
const { debounceAction } = this.props;
// -----> HERE I CALL DEBOUNCE ! <---------
e.stopPropagation();
debounceAction(this.buttonHandler, 400);
// -^^^ must return here
}
However, I would suggest going a step further to avoid future confusion. Simply invoke lodash's debounce
when you need it, rather than rewriting it multiple times in your code and leading to questionable method names.
Here is the most basic example of how you can wrap a click handler:
class Button extends React.Component {
handleClick = _.debounce((e) => {
alert('debounced click reaction')
}, 1000)
render() {
return <button onClick={this.handleClick}>CLICK ME</button>
}
}
ReactDOM.render(
<Button />,
document.getElementById('app')
);
<div id="app"></div>
<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://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>