I have a div in my React app and I need to handle both clicks and touches. However, when I tap on a mobile, it fires both events.
If I swipe on a mobile or if I click on a normal browser, it works fine, only one event is fired in each case.
How can I handle this tap issue to not fire both events?
<div
className={myClasses}
onClick={this.myHandle}
onTouchStart={this.myHandle}
>
</div>
There is a defined order of when the events get fired (source):
touchstart
Zero or more touchmove events, depending on movement of the finger(s)
touchend
mousemove
mousedown
mouseup
click
If you want to prevent a click event if a touch event is fired before, you can you can use event.preventDefault() in the touchend event handler to prevent the click event from firing.
function App() {
const handleClick = () => {
alert('click');
};
const handleTouchEnd = (event) => {
alert('touchend');
event.preventDefault();
};
return (
<button
type="button"
onClick={handleClick}
onTouchEnd={handleTouchEnd}
>
Click Me
</button>
);
}
However, this is not universally applicable. For example, you cannot prevent a click event by using a event.preventDefault() in a mousedown event. In case you are looking for a solution to this (not sure when this use case applies though), you would have to use a ref instead:
function App() {
const prevent = React.useRef(false);
const handleClick = () => {
if (!prevent.current) {
alert('click');
} else {
prevent.current = false;
}
};
const handleMouseDown = () => {
prevent.current = true;
alert('mousedown');
};
return (
<button
type="button"
onClick={handleClick}
onMouseDown={handleMouseDown}
>
Click Me
</button>
);
}
Solved this problem using similar events between touch and mouse. touchStart/mouseDown or touchEnd/mouseUp. It fires one or another, according to each situation.
<div
className={myClasses}
onMouseUp={this.myHandle}
onTouchEnd={this.myHandle}
>
</div>
To avoid onClick() on touch devices you should check if the page is opened in touch devices or not.
To check weather it is opened in touch devices or not:
if (typeof document !== 'undefined') {
var isTouch = 'ontouchstart' in document.documentElement;
}
Then modify {isTouch ? undefined : this.myHandle} to your mouse event:
<div
className={myClasses}
onClick={isTouch ? undefined : this.myHandle}
onTouchStart={this.myHandle}
>
</div>
This is a few years late but found a solution that was really easy to implement. Looks like this:
import ReactDom from 'react-dom';
export default class YourClass extends Component {
componentDidMount(){
ReactDOM.findDOMNode(this).addEventListener('touchstart', (e)=>{
e.preventDefault();
console.log("touchstart triggered");
});
}
}
Seems like it intercepts and stops all onClick calls on mobile which is exactly what I was looking for
Related
I am adding an event listener and checking if its level 1, but when I press the space key once, it fires 50times or more. Please help
document.addEventListener("keyup", function(e) {
if(level === 1){
if(e.code === "Space") {
console.log('space press');
click1();
}
}
});
Since this is tagged with React, given the code you have here and the issue you describe, it is almost certain that you are binding an event listener every render. Which means you are ending up with way more listeners than you want. What you need to do is use React when you are using React.
For example below, we have an input that logs on any keypress, and we also manually create an event listener. At first, when you type, you will get one log for each. However, once you click the button (triggering a rerender), you will start getting multiple "manual" events, but still the single "react" event:
class Hello extends React.Component {
constructor(props) {
super(props);
this.state = { count: props.count };
}
inc() {
this.setState(prev => ({count: prev.count+1}));
}
render() {
document.addEventListener("keyup", function(e) {
console.log('manual space press');
});
return <div onKeyUp={(e) => {
console.log('React: space press');
}}>
<button onClick={() => this.inc()}>{this.state.count}</button>
<input />
</div>
}
}
ReactDOM.render(<Hello count={0}/>, 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>
This is something called Event Bubblingwhich basically means that the event gets fired once on each parent element until it reached HTML.
you can learn about it here: https://dev.to/eladtzemach/event-capturing-and-bubbling-in-react-2ffg#:~:text=Event%20Bubbling%20and%20Capturing%20in%20React&text=Bubbling%20is%20as%20straightforward%20as,our%20example%20in%20the%20beginning.
you are able to prevent the default behavior but it's generally a good practice to leave it as is if you don't have a specific use for disabling it.
from the code snippet, I don't see why is this tagged with react but another reason for your problem is that you may be putting this code inside of your render() function or inside of any react life cycle function which is causing this snippet to run with each rerender leaving you with a punch of unwanted listeners which is not only functionality you don't want but also something that will slow down you app
overtime ie. until the user refresh the page.
useEffect(() => {
const handleEscape = (event) => {
if (event.keyCode === 27) {
console.log('Hello')
}
};
window.addEventListener('keydown', handleEscape);
return () => {
window.removeEventListener('keydown', handleEscape);
};
}, []);
I have a component which registers a key event during initialization.
This event triggers API call to fetch random Data.
useEffect(() => {
const keyUpEvent = (event) => {
if (event.code === "Enter") {
event.preventDefault();
fetchRandomData();
}
};
document.addEventListener("keyup", keyUpEvent);
fetchRandomData();
return () => {
setChord({});
document.removeEventListener("Keyup", keyUpEvent);
};
}, []);
But even with the above code, the event is not removed when I navigate between pages and trigger the event by key strokes ( Enter KEY ).
Based on the below image, this happens when I press the key once after multiple page navigations. ( MEMORY LEAK )
PROBLEM :
Why is react not removing the registered event? What is the proper way to remove event listeners..?
You are capitalizing incorrectly. You just change Keyup in removeEventListener to keyup.
I want to stop the click event from bubling up. Therefore I added e.stopPropagation() in my code. I always get a mistake in the console, that says: Uncaught TypeError: e.stopPropagation is not a function
What is the right way to set the stopPropagation in reactjs?
handleClick: function(index, e) {
e.stopPropagation();
...
},
The right way is to use .stopPropagation,
var Component = React.createClass({
handleParentClick: function() {
console.log('handleParentClick');
},
handleChildClick: function(e) {
e.stopPropagation();
console.log('handleChildClick');
},
render: function() {
return <div onClick={this.handleParentClick}>
<p onClick={this.handleChildClick}>Child</p>
</div>;
}
});
Example
Your event handlers will be passed instances of SyntheticEvent, a
cross-browser wrapper around the browser's native event. It has the
same interface as the browser's native event, including
stopPropagation() and preventDefault(), except the events work
identically across all browsers.
Event System
export default function myComponent(){
//buttonClicked:
const buttonClicked = (e) => {
e.stopPropagation();
// your code here...
}
//return:
return (
<div>
<input type='button'
onClick={ (e) => buttonClicked(e) }
></input>
</div>
)
}
The bounty expires in 7 days. Answers to this question are eligible for a +50 reputation bounty.
ajaykools wants to reward an existing answer:
Worth bounty, only way simulate clicks on dynamic elements like svg, g, circle, etc which are generated on page load.
I'm trying to simulate a .click() event on a React element but I can't figure out why it is not working (It's not reacting when I'm firing the event).
I would like to post a Facebook comment using only JavaScript but I'm stuck at the first step (do a .click() on div[class="UFIInputContainer"] element).
My code is:
document.querySelector('div[class="UFIInputContainer"]').click();
And here's the URL where I'm trying to do it: https://www.facebook.com/plugins/feedback.php...
P.S. I'm not experienced with React and I don't know really if this is technically possible. It's possible?
EDIT: I'm trying to do this from Chrome DevTools Console.
React tracks the mousedown and mouseup events for detecting mouse clicks, instead of the click event like most everything else. So instead of calling the click method directly or dispatching the click event, you have to dispatch the down and up events. For good measure I'm also sending the click event but I think that's unnecessary for React:
const mouseClickEvents = ['mousedown', 'click', 'mouseup'];
function simulateMouseClick(element){
mouseClickEvents.forEach(mouseEventType =>
element.dispatchEvent(
new MouseEvent(mouseEventType, {
view: window,
bubbles: true,
cancelable: true,
buttons: 1
})
)
);
}
var element = document.querySelector('div[class="UFIInputContainer"]');
simulateMouseClick(element);
This answer was inspired by Selenium Webdriver code.
With react 16.8 I would do it like this :
const Example = () => {
const inputRef = React.useRef(null)
return (
<div ref={inputRef} onClick={()=> console.log('clicked')}>
hello
</div>
)
}
And simply call
inputRef.current.click()
Use refs to get the element in the callback function and trigger a click using click() function.
class Example extends React.Component{
simulateClick(e) {
e.click()
}
render(){
return <div className="UFIInputContainer"
ref={this.simulateClick} onClick={()=> console.log('clicked')}>
hello
</div>
}
}
ReactDOM.render(<Example/>, document.getElementById('app'))
<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="app"></div>
If you don't define a class in your component, and instead you only declare:
function App() { ... }
In this case you only need to set up the useRef hook and use it to point/refer to any html element and then use the reference to trigger regular dom-events.
import React, { useRef } from 'react';
function App() {
const inputNameRef = useRef()
const buttonNameRef = useRef()
function handleKeyDown(event) {
// This function runs when typing within the input text,
// but will advance as desired only when Enter is pressed
if (event.key === 'Enter') {
// Here's exactly how you reference the button and trigger click() event,
// using ref "buttonNameRef", even manipulate innerHTML attribute
// (see the use of "current" property)
buttonNameRef.current.click()
buttonNameRef.current.innerHTML = ">>> I was forced to click!!"
}
}
function handleButtonClick() {
console.log('button click event triggered')
}
return (
<div>
<input ref={inputNameRef} type="text" onKeyDown={handleKeyDown} autoFocus />
<button ref={buttonNameRef} onClick={handleButtonClick}>
Click me</button>
</div>
)
}
export default App;
A slight adjustment to #carlin.scott's great answer which simulates a mousedown, mouseup and click, just as happens during a real mouse click (otherwise React doesn't detect it).
This answer adds a slight pause between the mousedown and mouseup events for extra realism, and puts the events in the correct order (click fires last). The pause makes it asynchronous, which may be undesirable (hence why I didn't just suggest an edit to #carlin.scott's answer).
async function simulateMouseClick(el) {
let opts = {view: window, bubbles: true, cancelable: true, buttons: 1};
el.dispatchEvent(new MouseEvent("mousedown", opts));
await new Promise(r => setTimeout(r, 50));
el.dispatchEvent(new MouseEvent("mouseup", opts));
el.dispatchEvent(new MouseEvent("click", opts));
}
Usage example:
let btn = document.querySelector("div[aria-label=start]");
await simulateMouseClick(btn);
console.log("The button has been clicked.");
Note that it may require page focus to work, so executing in console might not work unless you open the Rendering tab of Chrome DevTools and check the box to "emulate page focus while DevTools is open".
Inspired from previous solution and using some javascript code injection it is also possibile to first inject React into the page, and then to fire a click event on that page elements.
let injc=(src,cbk) => { let script = document.createElement('script');script.src = src;document.getElementsByTagName('head')[0].appendChild(script);script.onload=()=>cbk() }
injc("https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js",() => injc("https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js",() => {
class ReactInjected extends React.Component{
simulateClick(e) {
e.click()
}
render(){
return <div className="UFIInputContainer"
ref={this.simulateClick} onClick={()=> console.log('click injection')}>
hello
</div>
}
}
ReactDOM.render(<ReactInjected/>, document.getElementById('app'))
} ))
<div id="app"></div>
Kind of a dirty hack, but this one works well for me whereas previous suggestions from this post have failed. You'd have to find the element that has the onClick defined on it in the source code (I had to run the website on mobile mode for that). That element would have a __reactEventHandlerXXXXXXX prop allowing you to access the react events.
let elem = document.querySelector('YOUR SELECTOR');
//Grab mouseEvent by firing "click" which wouldn't work, but will give the event
let event;
likeBtn.onclick = e => {
event = Object.assign({}, e);
event.isTrusted = true; //This is key - React will terminate the event if !isTrusted
};
elem.click();
setTimeout(() => {
for (key in elem) {
if (key.startsWith("__reactEventHandlers")) {
elem[key].onClick(event);
}
}
}, 1000);
Using React useRef Hooks you can trigger a click event on any button like this:
export default const () => {
// Defining the ref constant variable
const inputRef = React.useRef(null);
// example use
const keyboardEvent = () => {
inputRef.current.handleClick(); //Trigger click
}
// registering the ref
return (
<div ref={inputRef} onClick={()=> console.log('clicked')}>
hello
</div>
)
}
This answer was inspired by carlin.scott code.
However, it works only with focusin event in my case.
const element = document.querySelector('element')
const events = ['mousedown', 'focusin']
events.forEach(eventType =>
element.dispatchEvent(
new MouseEvent(eventType, { bubbles: true })
)
)
This should be pretty simple but for some reason it isn't working, I'm getting the proper console.logs at the right time, but the focus isn't going to the correct place, please refer to my jsfiddle
https://jsfiddle.net/bqt0np9d/
function checkTabPress(e) {
"use strict";
// pick passed event of global event object
e = e || event;
if (e.keyCode === 9) {
if (e.shiftKey) {
console.log('back tab pressed');
firstItem.onblur=function(){
console.log('last a focus left');
lastItem.focus();
};
e.preventDefault();
}
console.log('tab pressed');
lastItem.onblur=function(){
console.log('last a focus left');
firstItem.focus();
};
e.preventDefault();
}
}
modal.addEventListener('keyup', checkTabPress);
I had to lock focus within a modal that we had used within a React component.
I added eventListner for KEY DOWN and collected Tab and Shift+Tab
class Modal extends Component {
componentDidMount() {
window.addEventListener("keyup", this.handleKeyUp, false);
window.addEventListener("keydown", this.handleKeyDown, false);
}
componentWillUnmount() {
window.removeEventListener("keyup", this.handleKeyUp, false);
window.removeEventListener("keydown", this.handleKeyDown, false);
}
handleKeyDown = (e) => {
//Fetch node list from which required elements could be grabbed as needed.
const modal = document.getElementById("modal_parent");
const tags = [...modal.querySelectorAll('select, input, textarea, button, a, li')].filter(e1 => window.getComputedStyle(e1).getPropertyValue('display') === 'block');
const focusable = modal.querySelectorAll('button, [href], input, select, textarea, li, a,[tabindex]:not([tabindex="-1"])');
const firstFocusable = focusable[0];
const lastFocusable = focusable[focusable.length - 1];
if (e.ctrlKey || e.altKey) {
return;
}
const keys = {
9: () => { //9 = TAB
if (e.shiftKey && e.target === firstFocusable) {
lastFocusable.focus();
}
if (e.target === lastFocusable) {
firstFocusable.focus();
}
}
};
if (keys[e.keyCode]) {
keys[e.keyCode]();
}
}
}
One of the problems is that you are using keyup instead of keydown. The keyup will only fire after the tab has already fired. However, making that change to your code results in the keyboard being trapped on one of the links. The code is flawed.
Here is some code that does what you want (using jQuery)
http://dylanb.github.io/javascripts/periodic-1.1.js
// Add keyboard handling for TAB circling
$modal.on('keydown', function (e) {
var cancel = false;
if (e.ctrlKey || e.metaKey || e.altKey) {
return;
}
switch(e.which) {
case 27: // ESC
$modal.hide();
lastfocus.focus();
cancel = true;
break;
case 9: // TAB
if (e.shiftKey) {
if (e.target === links[0]) {
links[links.length - 1].focus();
cancel = true;
}
} else {
if (e.target === links[links.length - 1]) {
links[0].focus();
cancel = true;
}
}
break;
}
if (cancel) {
e.preventDefault();
}
});
You can see a working version of this dialog here
http://dylanb.github.io/periodic-aria11-attributes.html
Click the text in one of the colored boxes to see the dialog pop up.
The e.preventDefault() has no effect on the keyup event (as the default browser action has already been fired)
Despite this, your example works. But only if there are links before and after the modal
If you change your HTML code with the following, adding one link before and one link after the modal; you will see that your focus is trapped in the modal:
other link
<div id="modal">
Link One
Link Two
</div>
other link
That's because there is no default browser action in such case, and then no action to prevent.
Trapping focus within a modal is very hard to do it on your own. If you're able to install third-party dependencies in your project, you can use the focus-trap package.
You can easily trap focus to any component with vanilla Javascript;
import { createFocusTrap } from 'focus-trap'
const modal = document.getElementById('modal')
const focusTrap = createFocusTrap('#modal', {
onActivate: function () {
modal.className = 'trap is-visible'
},
onDeactivate: function () {
modal.className = 'trap'
},
})
document.getElementById('show').addEventListener('click', function () {
focusTrap.activate()
})
document.getElementById('hide').addEventListener('click', function () {
focusTrap.deactivate()
})
or even React;
import React from 'react'
import ReactDOM from 'react-dom'
// Use the wrapper package of `focus-trap` to use with React.
import FocusTrap from 'focus-trap-react'
const Demo = () => {
const [showModal, setShowModal] = React.useState(false)
return (
<div>
<button onClick={() => setShowModal(true)}>show modal</button>
<FocusTrap active={showModal}>
<div id="modal">
Modal with with some{' '}
focusable elements.
<button onClick={() => setShowModal(false)}>
hide modal
</button>
</div>
</FocusTrap>
</div>
)
}
ReactDOM.render(<Demo />, document.getElementById('demo'))
I did a small write-up about the package here, which explains how to use it with either vanilla Javascript or React.
I thought I had solved trapping the focus on a modal by using tab, shift+tab, and arrow keys detection on keyup and keydown, focus, focusin, focusout on the first and last focusable elements inside the modal and a focus event for the window to set the focus back on the first focusable element on the form in case the focus "escaped" the modal or for situations like jumping from the address bar to the document using tab, but something weird happened. I had activated "Caret Browsing" in one of my browsers accidently, and that's when I realized all methods to trap focus failed miserably. I personally went on a rabbit whole to solve this for a modal. I tried focusin, focusout on the modal, matching focus-within pseudo classes, {capture: true} on the focus event from the modal and window, nothing worked.
This is how I solved it.
I recreated the modal to have a different structure. For the sake of simplicity, I am omitting a lot of things, like the aria attributes, classes, how to get all focusable elements, etc.
<component-name>
#shadow-root (closed)
<div class="wrapper">
<div class="backdrop"></div>
<div class="window>
<div tabindex="0" class="trap-focus-top"> </div>
<div class="content">
<div class="controls"><!-- Close button, whatever --></div>
<header><slot name="header"></slot></header>
<div class="body"><slot></slot></div>
<footer><slot name="footer"></slot></footer>
</div>
<div tabindex="0" class="trap-focus-bottom"> </div>
</div>
</div>
</component-name>
Search the contents div for focusable elements, to save the first and last one. If you find only one then that one will be first and last. If you find zero, then set the div for the body (.body) tabindex to "0" so that you have at least one element to set the focus on.
Before and after the content div we have two focusable divs, trap-focus-top and trap-focus-bottom, the first one when getting focus will jump the focus to the last focusable element detected on step one, and the second one will jump the focus to the first focusable element detected on step one. No need to capture any key events, just focus event on these elements. If you notice the non-breaking space on trap-focus elements, this is for mimicking content, because I noticed that the arrow keys went through these elements without firing any events when empty. When I realized this I added some content and everything worked, so I added a non-breaking space and styled the elements so that they do not occupy any space.
Capture all focus events from the window with the use capture flag set to true, so that every focus event whose target was different to the component (focus events inside the shadow-root wont't be captured with the actual target but the component itself) will result in the focus being set on the modal elements again.
Now there's another problem, let's say there's zero focusable elements on your modal outside of any controls, like a button to close the modal, then we set tabindex to 0 on the modal's body, your focus should go from the close button to the modal's body and vice versa, now, the caret browsing won't work on the content because the div.body will have the focus, not the actual content. This means I have to create another function that places the cursor at the beginning of the content whenever the body receives the focus.
startCursor = () => {
/* componentbody is a placeholder for the element with the actual content */
let text = componentbody.childNodes[0];
if (text) {
let range = new Range();
let selection = document.getSelection();
range.setStart(text, 0);
range.setEnd(text, 0);
selection.removeAllRanges();
selection.addRange(range);
componentbody.scrollTop = 0;/* In case the body has a scrollbar */
}
}
For anyone out there, this is what worked for me.