One-time events: These are those events that only execute the event listener only once. Suppose we have created a button and added a click event. We create a one-time event if it only executes once, irrespective of the fact that a user clicks the button several times.
Suppose we have created a button that fetches the data from an API, if we are not adding a one-time event on it then it fetches the data from API on every click of the user, ignoring the previous responses. Because of this, it overloads our system and slows down the performance, and also gives a very bad user experience.
What happens if we do not use a one-time event listener?
Event listener executes its functions every time when it listens to that listener from the user. Let’s say “click“, so whenever the user clicks that particular button, it every time starts executing the same instructions.
One time event listener creation: We use removeEventListener() to remove the event listener after it executes only once. It is not executing even after several clicking of the button because the event listener is removed from the button.