Mouse hover in React - javascript

I'm trying to display a div when the mouse is over another div element. I've managed to do so via onMouseEnter and onMouseLeave.
The issue here is that if you quickly move from one div to another (it's an array of divs that contain data about a product), the value of index[0] becomes true.
The way it works is that I have an array initialised to false when the mouse enters one of them, it becomes true and shows the div that I wanted. Once it leaves, it set it back to false.
this.state = {
isProductsHovering: new Array(this.props.currentProducts.length).fill(false)
};
handleMouseHover = (idx) => {
this.setState({
isProductsHovering: update(this.state.isProductsHovering, {
[idx]: { $set: !this.state.isProductsHovering[idx] }
})
})
}
render() {
return this.props.currentProducts.map((product, idx) => {
return <Fragment key={idx}>
<div className="product-grid-view col-6 col-md-4" >
<div
className=" product-holder"
onMouseEnter={this.handleMouseHover.bind(this, idx)}
onMouseLeave={this.handleMouseHover.bind(this, idx)}>
<div className="image-container" align="center">
<img src={"/img/product-3.jpg"} alt="" />
{
this.state.isProductsHovering[idx] &&
<div className="product-buttons">
<Link to={`products/${product.id}`} className="btn-detail" text="View Details" />
<Link to='#' className="btn-cart" icons={["icon-cart", "icon-plus"]} />
</div>
}
</div>
<div className="details-holder">
<span className="part-text">{product.desc}</span><br />
<span className="manufacturer-text">{product.manufacturer.name}</span>
<div className="product-review_slide">
<Stars values={product.averageRating} {...starsRating} />
<span className="product-review">{getLength(product.reviews)} review</span>
</div>
<span className="product-price">{product.salesPrice.toFixed(2)}</span>
<span className="product-currency">SR</span>
</div>
</div>
</div>
</Fragment>
})
}
Update
I've made a stackblitz project to reproduce the same issue as suggested:
https://stackblitz.com/edit/react-mouse-hover.
For everyone that wants to see what I mean. I've attached a photo of the issue. If you move the mouse over the two divs (up and down as quick as you can), this what happens:
mouse hover broken

For situation like this, I wouldn't rely on array and index to make it work. You are further complicating your handleMouseHover functions and the checking of isHovering.
A 'more React' way of dealing with this situation is simply make each Product a component itself. And this Product component will have its own state of isHovered and handleOnHover method, that way you create a more concise and reliable code without having to rely on array index at all:
App.js can be as simple as this:
class App extends Component {
render() {
return (
<div>
{
data.map(product =>
<Product product={product} />
)
}
</div>
)
}
}
A new Product.js:
import React from 'react'
import ReactHoverObserver from 'react-hover-observer';
export default class Product extends React.Component {
render() {
const { product } = this.props
return (
<ReactHoverObserver className="product-grid-view col-6 col-md-4">
{
({isHovering}) => (
<div className=" product-holder">
<div className="image-container" align="center">
<img src={"/img/product-3.jpg"} alt="" />
{
isHovering &&
<div className="product-buttons">
<button className="btn-detail">View Details</button>
</div>
}
</div>
<div className="details-holder">
<span className="part-text">{product.desc}</span><br />
<span className="manufacturer-text">{product.manufacturer.name}</span>
<div className="product-review_slide">
<span className="product-review">0 review</span>
</div>
<span className="product-price">{product.salesPrice.toFixed(2)}</span>
<span className="product-currency">Currency</span>
</div>
</div>
)
}
</ReactHoverObserver>
)
}
}
I have put the moficiation in Stackblitz: https://stackblitz.com/edit/react-mouse-hover-2cad4n

Liren's answer is good advice and will help simplify the code. One thing I also noticed is that occasionally the HoverObserver won't 'hear' an event, and since the hover enter and hover exit events are listening to the same event, then the display state for the button will become reversed (i.e., it will show when the mouse is NOT hovering and hide when the mouse hovers over the observer).
I would recommend getting rid of the ReactHoverObserver HOC and instead just listen for the onMouseOver for hover enter and onMouseLeave for hover exit. That way, even if the div doesn't register a hover enter or exit, it will easily reset because onMouseOver will toggle the display state to true and onMouseLeave will reliably set the button's display state to false.
See here for those events in the docs:
https://reactjs.org/docs/events.html#mouse-events

The way you trigger it (from array or from a component) is semantics , the real issue is that these events don't always fire.
I had the same issue , apparently the events of react are not that reliable.
In my case I could live in a situation where a tooltip does not close , but not in the situation where 2 tooltips are open. In order to solve my issue , I returned to good old dom manipulation - Every time a tooltip appeared , it made all the other ones invisible.
It looked something like this :
showTooltip() {
// Clear old tooltips, EventTooltip is the name of my tooltip class.
Array.from(document.getElementsByClassName('EventTooltip'))
.forEach(tooltip=>tooltip.style = 'display:none;')
this.setState({showTooltip: true})
}
hideTooltip() {
this.setState({showTooltip: false})
}

Related

How to hide/show a div in React?

I want to create a button to show and hide a div.
In the first div (div1) I have a table and in the second div (div2) I have a chart.
When a user clicks the button (with bar icon), should see the div2 (chart) and when the user clicks again it should return div1 (table).
How can I do it?
tables.js
export function IncomeTables({firminfo, title, arr_number, financials, balance}) {
...
...
return <Card>
<div id="div1">
<Table>
<head>
<tr>
<th colSpan="5">{title} <button style={{float:"right"}} className="btn btn-primary" ><FaChartBar/></button></th>
</tr>
...
</thead>
...
</Table>
</div>
<div id="div2">
<BarChart>
...
</BarChart>
</div>
</Card>
This is how you do it:
export default function App() {
let [show, setShow] = React.useState(false);
return (
<div>
{show ? <div>Hello</div> : <div>Another div</div>}
<button
onClick={() => {
setShow(!show);
}}
>
Click
</button>
</div>
);
}
But when say instead of divs you render different types of components, when switching to another component, the previous one will be unmounted, and all state will be gone (due to reconciliation). In such cases you may want to store state in parent (e.g. App), so that state is not lost.
Or alternatively you may change display property of the div you want to show/hide, based on state variable; in that case state will not be lost, because you are not unmounting anything just changing a CSS property.

How to render a component outside the component that contains the function that renders the first component?

The situation is a bit complicated:
inside a component called "LeftSectionHeader" I have a div, which when clicked must render a component;
the component to be rendered is called "ProfileMenu", and is basically a div that must be rendered on top of "LeftSectionHeader" itself and another div;
All these components are rendered inside another component called "Main".
The problem is that if I define the function inside "LeftSectionHeader", "ProfileMenu" will be rendered inside, while I need it to not only be rendered outside, but even cover it; that's why you'll see some boolean vars inside "Main", because that is the only way i could render it, but it still doesn't cover the other divs. I'll attach the code of each component and how the final result should look below.
LeftSctionHeader:
function LeftSectionHeader(){
return(
<div class="left-section-header">
<div class="crop" ><img src="./images/profiles/anonimous.png" /></div>
</div>
);
}
The div belonging to the "crop" class is the one that must be clicked to render "ProfileMenu"
ProfileMenu:
function ProfileMenu(){
return(
<div class="profile-side-menu">
//A lot of boring stuff
</div>
);
}
There are some functions related to this component, but they are not important, so I didn't put them, just ignore it
Main:
var p=true;
var m=true;
function Main(){
return(
<div class="main">
<Header />
<div class="left-section">
{m ? <div><LeftSectionHeader /><LangMenu /></div> : <ProfileMenu />}
</div>
{p ? <PostPage /> : <NoPostsMessage />} //Ignore this line
</div>
);
}
Before clicking on the orange div
After clicking
This might help as guidline, hopefully!
function LeftSectionHeader({ onClick }){
return(
<div class="left-section-header" onClick={onClick}>
<div class="crop" ><img src="./images/profiles/anonimous.png" /></div>
</div>
);
}
function Main(){
const [showProfile, setShowProfile] = useState(false);
return(
<div class="main">
<Header />
<div class="left-section">
{!showProfile ? (
<div>
<LeftSectionHeader onClick={() => setShowProfile(true)} />
<LangMenu />
</div>
) : <ProfileMenu />}
</div>
{p ? <PostPage /> : <NoPostsMessage />} //Ignore this line
</div>
);
}
The simplest solution might be to pass a handler into the header component to toggle the menu:
function App () {
const [showMenu, setShowMenu] = useState();
return (
<div>
<Header onMenuToggle={() => setShowMenu(!showMenu)} />
{ showMenu && <Menu /> }
</div>
)
}
function Header ({ onMenuToggle }) {
<div onClick={onMenuToggle}>...</div>
}
Caveat: This will cause the entire App component to re-render when the menu state changes. You can mitigate this by either
A) placing the menu state closer to where it's actually needed, like in the sidebar component instead of at the top, or
B) using a context or other orthogonal state store.
Another approach would be to leave the state handling in the LeftSectionHeader component and then use a React portal to render the menu elsewhere in the DOM.

React Component "closing" when lost focus

I'm trying to create a select2 style component in React.
I have got 90% functionality down, the one bit I just can't fathom is hiding the result box when the user clicks away
The render method is:
render() {
let resultBlock;
if (this.state.showSearch) {
resultBlock = (
<div className="search-input-container" onBlur={this.onBlur}>
<div className="search-input-results">
<input
type="text"
name={this.props.name}
placeholder={this.props.placeholder}
className="form-control"
onChange={this.inputKeyUp}
autoComplete="false" />
<ul>
{this.state.items.map((item, i) => <li key={i} data-value={item.id} onClick={this.itemSelected} className={item.isSelected ? 'selected' : ''}>{item.text}</li>)}
</ul>
</div>
</div>
);
}
let displayBlock;
if (this.props.value.text) {
displayBlock = this.props.value.text;
} else {
displayBlock = <span className="placeholder">{this.props.placeholder}</span>;
}
return (
<div className="form-group">
<label htmlFor={this.props.name}>{this.props.label}:</label>
<div className="form-input">
<div className="searchable-dropdown" onClick={this.revealSearch}>
{displayBlock}
<div className="arrow"><i className="fa fa-chevron-down" aria-hidden="true" /></div>
</div>
{resultBlock}
</div>
</div>
);
}
I've tried moving onBlur={this.onBlur} around, but it only fires if the <input... had focus before one clicked away.
It can't be that complicated, the only approach I thought of, is attaching a global click handler to the page, and diff'ing clicks to understand if a user hasn't clicked on my component. But this seems over engineered.
How can this be achieved?
I achieved this functionality by:
Putting this in the constructor:
this.windowClick = this.windowClick.bind(this);
(From what dfsq said) Put this in componentDidMount:
if (window) {
window.addEventListener('click', this.windowClick, false);
}
This event handler:
windowClick(event) {
event.preventDefault();
if (event.target.classList.contains('searchable-marker')) {
return;
} else {
this.setState({
showSearch: false
});
}
}
Where searchable-marker is just a class I put on all the div's, ul's, li's and inputs to make sure that if I clicked one of these, it wouldn't close the the box.
Adding the unmount:
componentWillUnmount() {
window.removeEventListener('click', this.windowClick, false);
}
what you can try doing is onBlur you could change the value of this.state.showSearch = false and when this condition is satisfied add a className="hide" (hide{display: none}) by creating a custom function which returns a classname as a string.

Don't trigger onClick for nested child elements

I have a simple modal component:
function Modal(props) {
return (
<div className={cx(styles.overlay, { show: props.show })} onClick={props.onClose}>
<div className={styles.modal}>
<span className={styles.closeBtn} onClick={props.onClose} />
{props.children}
</div>
</div>
)
}
the onClose prop triggers closing the modal, hence I attach it to styles.overlay (dark overlay that you typically see on modals that when clicked dissmises it) and to styles.closeBtn (a close button for modal).
The whole flow works besides the fact that anything inside styles.overlay when clicked on also dismisses the modal, which is not functionality I was after, hence I need to only dismiss it if that specific element is clicked not its children.
function Modal(props) {
return (
<div className={cx(styles.overlay, { show: props.show })} onClick= {props.onClose}>
<div className={styles.modal} onClick={e => e.preventDefault()}>
<span className={styles.closeBtn} onClick={props.onClose} />
{props.children}
</div>
</div>
)
}
I think, the best way is to have your overlay and your modal in two separate div, but this should work.
Add onClick(e)={e.stopPropagation();} to the modal dialog's click handler; this should prevent it from propagating to the overlay.
Hope it works! Good luck!

Showing/hiding elements in React

having a little trouble here when trying to show or hide divs in react.
I have three classes:
1. RunningOrder Section
2. RunningOrder
3. Story
running order section is the main section, which renders the running order class, and running order renders the Story class.
I have a toggle switch in running order section which toggles the 'displayStory' state in running order and running order passes the 'displayStory' bool state as a prop to story.
toggle in RunningOrder Section:
_triggerChildDisplay: function () {
this.refs.child.displayStory();
},
<Toggle
tooltip = {'Auto Sequence'}
onToggle = {this._triggerChildDisplay}
/>
for (let storyId in ro.stories) {
allStories.push(<Story key={storyId} story={ro.stories[storyId]} displayStory={this.state.displayStory}/>)
};
state and prop in Running Order:
displayStory: function() {
this.setState({
displayStory: !this.state.displayStory
});
},
for (let storyId in ro.stories) {
allStories.push(<Story key={storyId} story={ro.stories[storyId]} displayStory={this.state.displayStory}/>)
};
render method of story
if(allItems.length > 0) {
return (
<div className="story-container">
<div className="story-label-container">
<div className="story-slug">
<span className="story-title">
{story.slug}
</span>
{/*<span className="storyItemLength">
{allItems.length}
</span>*/}
<span className="story-sequence-control">
<OverlayTrigger placement="top" overlay={autoSequenceTooltip}>
<Toggle
label = {<SequenceIcon />}
disabled = {allItems.length > 0? false : true}
tooltip = {'Auto Sequence'}
onToggle = {this.toggled}
/>
</OverlayTrigger>
</span>
</div>
</div>
{itemList}
</div>
);
} else {
return (
<div className={this.props.displayStory ? "story-container" : "hidden story-container"}>
<div className="story-label-container">
<div className="story-slug">
<span className="story-title">
{story.slug}
</span>
{/*<span className="storyItemLength">
{allItems.length}
</span>*/}
<span className="story-sequence-control">
<OverlayTrigger placement="top" overlay={autoSequenceTooltip}>
<Toggle
label = {<SequenceIcon />}
disabled = {allItems.length > 0? false : true}
tooltip = {'Auto Sequence'}
onToggle = {this.toggled}
/>
</OverlayTrigger>
</span>
</div>
</div>
{itemList}
</div>
);
}
}
I only want to be able to toggle the display of elements in story if the allItems array has length greater than 0, hence the two returns.
Running order loops and pulls data from a server, the running order class returns 3 items each of these items have multiple items in them rendered by story which i need to toggle the display of.
Now my code is working, but for some reason I can only toggle the display (the hidden css class) in the last element returned by running order. so if running order returned:
<div 1>
<items />
</div>
<div 2>
<items />
</div>
<div 3>
<items />
</div>
the display toggle only affects the items in div 3.
*******Update:** instead of a single toggle for all elements rendered by running order I have put the toggle switch in running order and it works fine, so it is something with call the reffs here: this.refs.child.displayStory();

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