You’ve Got Options for Removing Event Listeners
Tags: javascript, events
Published: 2023-01-28 23:06:59

---
title: You’ve Got Options for Removing Event Listeners
published: true
date: 2023-01-28 05:00:00 UTC
tags: JavaScript, events
canonical_url: https://macarthur.me/posts/options-for-removing-event-listeners
---

Cleaning up your code in runtime is a non-negotiable part of building efficient, predictable applications. One of the ways that’s done in JavaScript is by stewarding event listeners well — specifically, removing them when they’re no longer needed.

There are several approaches available to do this, each with its own set of trade-offs that make it more appropriate in certain circumstances. We’re gonna run through a few of the most often used tactics, as well as a few considerations to keep in mind when you’re trying to decide which is best for the job at any given time.

We’ll be tinkering with the following setup — a button with a single `click` event listener attached:

```
<button id="button">Do Something</button>

<script>
document.getElementById('button').addEventListener('click', () => {
	console.log('clicked!');
});
</script>

```

Using [Chrome’s](https://developer.chrome.com/docs/devtools/console/utilities/#getEventListeners-function)[`getEventListeners()`](https://developer.chrome.com/docs/devtools/console/utilities/#getEventListeners-function)[function](https://developer.chrome.com/docs/devtools/console/utilities/#getEventListeners-function), you’d see just one listener attached to that element:

In the event that you’d need to remove that listener, here’s what you might reach for.

## Using .removeEventListener()

It’s probably the most obvious, but also the one with the most potential to threaten your sanity. The `.removeEventListener()` method accepts three parameters: the type of listener to remove, the callback function for that listener, and an options object.

But herein lies the (potentially) tricky part: those exact parameters must _exactly_ match what were used when then the listener was set up, including the _same reference_ in to the callback in memory. Otherwise, `.removeEventListener()` does nothing.

With that in mind, this would be totally ineffective:

```
document.getElementById('button').addEventListener('click', () => {
	console.log('clicked!');
});

document.getElementById('button').removeEventListener('click', () => {
	console.log('clicked!');
});

```

Even though that callback _looks_ identical to the one originally attached, it’s not the _same reference_. The solution to this is to set the callback to a variable and reference it in both `.addEventListener()` and `.removeEventListener()`.

```
const myCallback = () => {
  console.log('clicked!');
};

document.getElementById('button').addEventListener('click', myCallback);
document.getElementById('button').removeEventListener('click', myCallback);

```

Or, for particular use cases, you could also remove the listener by referencing a pseudo-anonymous function from within the function itself:

```
document
  .getElementById('button')
  .addEventListener('click', function myCallback() {
    console.log('clicked!');

    this.removeEventListener('click', myCallback);
  });

```

Despite its particularity, `.removeEventListener()` has the advantages of being very explicit in its purpose. There’s zero doubt as to what it’s doing when you’re reading through the code.

## Using `.addEventListener()`’s `once` Option

The `.addEventListener()` method comes with a tool to help clean itself up if it’s intended for a one-time use: the `once` option. It’s about as simple as it sounds. If it’s set to `true`, the listener will automatically remove itself after first being invoked:

```
const button = document.getElementById('button');

button.addEventListener('click', () => {
	console.log('clicked!');
}, { once: true });

// 'clicked!'
button.click();

// No more listeners!
getEventListeners(button) // {} 

```

Assuming it fits your use case, this approach might be appropriate if you’re keen on using an anonymous function, given that your listener only needs to be invoked once.

## Cloning & Replacing the Node

Sometimes, you don’t know about all the listeners active on a given node, but you do know you want to nuke them. In that case, it’s possible to clone the entire node and replace itself with that clone. Using the [`.cloneNode()`](https://developer.mozilla.org/en-US/docs/Web/API/Node/cloneNode)[method](https://developer.mozilla.org/en-US/docs/Web/API/Node/cloneNode), none of the listeners attached via `.addEventListener()` will be carried over, giving it a clean slate.

Back in the stone age of client-side JavaScript, you would’ve seen this done by querying up to the parent, and replacing a particular child node with a clone:

```
button.parentNode.replaceChild(button.cloneNode(true), button);

```

But in modern browsers, that can be simplified with `.replaceWith()`:

```
button.replaceWith(button.cloneNode(true));

```

The one thing that could potentially trip you up here is that intrinsic listeners _are preserved,_ meaning a button with an `onclick` attribute would still fire as defined:

```
<button id="button" onclick="console.log('clicked!')">
	Do Something
</button>

```

In all, it’s an option worth reaching for if you need to indiscriminately remove listeners of any sort with brute force. On the downside, however, it suffers from being less obvious about its purpose. Some might go so far as to call it a hack.

## Using `AbortController()`

This one’s new to me. I literally just read about it when I came across [this tweet](https://twitter.com/calebporzio/status/1617939346786779136?s=20&t=hudHTQt9g3BBoDVpLwoM9A) from Caleb Porzio. If you’re like me, you might’ve only heard of an `AbortController` being used to [cancel](https://javascript.info/fetch-abort#using-with-fetch)[`fetch()`](https://javascript.info/fetch-abort#using-with-fetch)[requests](https://javascript.info/fetch-abort#using-with-fetch). But it’s apparently more flexible than that.

As of recently, `.addEventListener()` can be configured with a `signal` for imperatively aborting/removing a listener. When the respective controller calls `.abort()`, that signal will trigger the listener to be removed:

```
const button = document.getElementById('button');
const controller = new AbortController();
const { signal } = controller;

button.addEventListener('click', () => console.log('clicked!'), { signal });

// Remove the listener!
controller.abort();

```

The most apparent advantage to this might be the ergonomics. It’s (in my opinion) a much clearer way of removing a listener without the potential gotcha of dealing with `.removeEventListener()`. But there’s a more tactical advantage too: you can use one signal to remove multiple listeners, of any sort, all at once. And using anonymous functions is totally fine too:

```
const button = document.getElementById('button');
const controller = new AbortController();
const { signal } = controller;

button.addEventListener('click', () => console.log('clicked!'), { signal });
window.addEventListener('resize', () => console.log('resized!'), { signal });
document.addEventListener('keyup', () => console.log('pressed!'), { signal });

// Remove all listeners at once:
controller.abort();

```

The only cause for hesitancy I came across is browser support. It’s a relatively new feature, with full support existing in Chrome [only since 2021](https://chromium-review.googlesource.com/c/chromium/src/+/2657187) (v90). So, keep this in mind if you need to support browser versions beyond only a couple years old.

## Which Should I Choose?

As with everything else, “it depends.” Still, here’s how I might choose one over the other at a moment’s notice:

- Use `.removeEventListener()` if the callback function is assigned to a variable and within easy reach of where the listener was added.
- Use the `once` option in `.addEventListener()` if you need to fire a callback only once (duh).
- Use the clone & replace approach if you need to indiscriminately nuke multiple listeners in one fell swoop.
- Use `AbortController()` if you have a series of listeners you’d like to imperatively remove at once, or if you just like the syntax.

## What’s Missing?

It’s very possible I’m missing another option in addition to these. If you happen to have one, feel free to drop a comment or let me know by some other means. At the very least, I hope this helps to mentally organize some of the the several paths available to clean up event listeners, and to also help prep your brain for the next time you need to manage them in your code.