JAVASCRIPT

.removeEventListener()

eventTarget.addEventListener("event", eventHandlerFunction);
 
eventTarget.removeEventListener("event", eventHandlerFunction);

reference of event listener funtion to remove

element.addEventListener('click',element.fn=function fn() {
    //  Event Code
}, false);
element.removeEventListener('click',element.fn, false);

How to remove an event listener from an element?

const off = (el, evt, fn, opts = false) => el.removeEventListener(evt, fn, opts);

const fn = () => console.log('!');
document.body.addEventListener('click', fn);
off(document.body, 'click', fn); // no longer logs '!' upon clicking on the page