How to ensure an event listener is only fired once in JavaScript

1. Using the once option

We can pass an object as an argument to the addEventListener method and specify that the event is only handled once. This is achieved by passing the property once to the object. If we set once to true, the event will only be fired once.

let btn = document.getElementById('btn');
btn.addEventListener("click", function() {

    // onClick code

}, {once : true});

2. Removing the event listener once the event is…