Check out example codes for "removeeventlistener". It will help you in understanding the concepts better.

Code Example 1

var someEventHander=function(event){
	console.log("do something");
}

//add listener
document.getElementById("someid").addEventListener('click',someEventHander);

//remove listener 
document.getElementById("someid").removeEventListener('click',someEventHander);

Code Example 2

//                             type         function
element.removeEventListener("mousedown", handleMouseDown)
// full type list available here: https://developer.mozilla.org/en-US/docs/Web/Events

Code Example 3

element.removeEventListener(event, listener, useCapture)

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