🎹 An accessible accordion in <1kb

• 🔬 Tiny (<1kb gzipped)
• 💕 Accessible by default
• ✨ Easy to style and animate
• ⚙️ Highly configurable

npm i sqzbx

Apply data-sqzbx-button and data-sqzbx-panel attributes as illustrated below. sqzbx doesn't care about the structure of your markup as long as the following are true:

• There are an equal number of data-sqzbx-button elements and data-sqzbx-panel elements
• All data-sqzbx-button elements are actually buttons
• All data-sqzbx-panel elements contain exactly 1 child element

<div class="accordion">
  <button data-sqzbx-button>Button 1</button>
  <div data-sqzbx-panel>
    <p>Panel 1</p>
  </div>
  <button data-sqzbx-button>Button 2</button>
  <div data-sqzbx-panel>
    <p>Panel 2</p>
  </div>
  <button data-sqzbx-button>Button 3</button>
  <div data-sqzbx-panel>
    <p>Panel 3</p>
  </div>
</div>

Add some CSS. Below are the minimal recommended styles, but here is a more advanced example

[data-sqzbx-panel] {
  overflow: hidden;
  max-height: 0;
}

[data-sqzbx-panel][aria-hidden='true'] {
  max-height: 0 !important;
}

Initialize and mount sqzbx

import sqzbx from 'sqzbx'

const element = document.querySelector('.accordion')
const accordion = sqzbx(element)

accordion.mount()

sqzbx takes an options object as its second parameter

sqzbx(element, options)

default: false

When multiple is set to true, any number of panels may be open at the same time. By default, when a user opens a new accordion item, the previously open item will collapse.

default: false

When collapsible is set to true, panels that are already open may be collapsed. By default, open panels only collapse when a user opens a different one.

default: null

Sets the initially expanded accordion item.

default: true

In order to make animation easy, sqzbx measures the height of the firstElementChild for each panel and automatically updates these values on window resize. Set resize to false to remove this automatic resize behavior and call the .resize() method manually.

Fired immediately after a user selects a new accordion item.

accordion.on('expand', ({ index, button, panel, open }) => {})

Fired immediately after an accordion item is collapsed.

accordion.on('collapse', ({ index, button, panel, open }) => {})

Fired on expanding panel transitionend (which means that this event only fires if the panel has a CSS transition).

accordion.on('expanded', ({ index, button, panel, open }) => {})

Fired on collapsing panel transitionend (which means that this event only fires if the panel has a CSS transition).

accordion.on('collapsed', ({ index, button, panel, open }) => {})

The callback receives an accordion item object containing index of the item, button element, panel element, and an open boolean. Returns a function to unsubscribe from the event.

const offExpand = accordion.on('expand', ({ index, button, panel, open }) => {})

offExpand() // removes expand event listener

Sets up all aria attributes and attaches event listeners. Must be called after initializing an instance of sqzbx. Returns an unmount function to remove all event listeners which is useful for sites with client-side navigation.

let unmount

function init() {
  unmount = accordion.mount()
}

function destroy() {
  unmount()
}

Manually update the panel height. Useful when paired with the resize option set to false to disable the automatic resizing behavior and manage this yourself.

import sqzbx from 'sqzbx'

const element = document.querySelector('.accordion')
const accordion = sqzbx(element, { resize: false })

window.addEventListener('resize', accordion.resize)
accordion.mount()