Binding multiple events to a listener (without JQuery)?
JavascriptJqueryTouchAddeventlistenerJavascript Problem Overview
While working with browser events, I've started incorporating Safari's touchEvents for mobile devices. I find that addEventListener
s are stacking up with conditionals. This project can't use JQuery.
A standard event listener:
/* option 1 */
window.addEventListener('mousemove', this.mouseMoveHandler, false);
window.addEventListener('touchmove', this.mouseMoveHandler, false);
/* option 2, only enables the required event */
var isTouchEnabled = window.Touch || false;
window.addEventListener(isTouchEnabled ? 'touchmove' : 'mousemove', this.mouseMoveHandler, false);
JQuery's bind
allows multiple events, like so:
$(window).bind('mousemove touchmove', function(e) {
//do something;
});
Is there a way to combine the two event listeners as in the JQuery example? ex:
window.addEventListener('mousemove touchmove', this.mouseMoveHandler, false);
Any suggestions or tips are appreciated!
Javascript Solutions
Solution 1 - Javascript
Some compact syntax that achieves the desired result, POJS:
"mousemove touchmove".split(" ").forEach(function(e){
window.addEventListener(e,mouseMoveHandler,false);
});
Solution 2 - Javascript
In POJS, you add one listener at a time. It is not common to add the same listener for two different events on the same element. You could write your own small function to do the job, e.g.:
/* Add one or more listeners to an element
** @param {DOMElement} element - DOM element to add listeners to
** @param {string} eventNames - space separated list of event names, e.g. 'click change'
** @param {Function} listener - function to attach for each event as a listener
*/
function addListenerMulti(element, eventNames, listener) {
var events = eventNames.split(' ');
for (var i=0, iLen=events.length; i<iLen; i++) {
element.addEventListener(events[i], listener, false);
}
}
addListenerMulti(window, 'mousemove touchmove', function(){…});
Hopefully it shows the concept.
Edit 2016-02-25
Dalgard's comment caused me to revisit this. I guess adding the same listener for multiple events on the one element is more common now to cover the various interface types in use, and Isaac's answer offers a good use of built–in methods to reduce the code (though less code is, of itself, not necessarily a bonus). Extended with ECMAScript 2015 arrow functions gives:
function addListenerMulti(el, s, fn) {
s.split(' ').forEach(e => el.addEventListener(e, fn, false));
}
A similar strategy could add the same listener to multiple elements, but the need to do that might be an indicator for event delegation.
Solution 3 - Javascript
Cleaning up Isaac's answer:
['mousemove', 'touchmove'].forEach(function(e) {
window.addEventListener(e, mouseMoveHandler);
});
EDIT
ES6 helper function:
function addMultipleEventListener(element, events, handler) {
events.forEach(e => element.addEventListener(e, handler))
}
Solution 4 - Javascript
ES2015:
let el = document.getElementById("el");
let handler =()=> console.log("changed");
['change', 'keyup', 'cut'].forEach(event => el.addEventListener(event, handler));
Solution 5 - Javascript
For me; this code works fine and is the shortest code to handle multiple events with same (inline) functions.
var eventList = ["change", "keyup", "paste", "input", "propertychange", "..."];
for(event of eventList) {
element.addEventListener(event, function() {
// your function body...
console.log("you inserted things by paste or typing etc.");
});
}
Solution 6 - Javascript
I have a simpler solution for you:
window.onload = window.onresize = (event) => {
//Your Code Here
}
I've tested this an it works great, on the plus side it's compact and uncomplicated like the other examples here.
Solution 7 - Javascript
One way how to do it:
const troll = document.getElementById('troll');
['mousedown', 'mouseup'].forEach(type => {
if (type === 'mousedown') {
troll.addEventListener(type, () => console.log('Mouse is down'));
}
else if (type === 'mouseup') {
troll.addEventListener(type, () => console.log('Mouse is up'));
}
});
img {
width: 100px;
cursor: pointer;
}
<div id="troll">
<img src="http://images.mmorpg.com/features/7909/images/Troll.png" alt="Troll">
</div>
Solution 8 - Javascript
AddEventListener take a simple string that represents event.type. So You need to write a custom function to iterate over multiple events.
This is being handled in jQuery by using .split(" ") and then iterating over the list to set the eventListeners for each types
.
// Add elem as a property of the handle function
// This is to prevent a memory leak with non-native events in IE.
eventHandle.elem = elem;
// Handle multiple events separated by a space
// jQuery(...).bind("mouseover mouseout", fn);
types = types.split(" ");
var type, i = 0, namespaces;
while ( (type = types[ i++ ]) ) { <-- iterates thru 1 by 1
Solution 9 - Javascript
You can also use prototypes to bind your custom function to all elements
Node.prototype.addEventListeners = function(eventNames, eventFunction){
for (eventName of eventNames.split(' '))
this.addEventListener(eventName, eventFunction);
}
Then use it
document.body.addEventListeners("mousedown touchdown", myFunction)