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a-expandable

A collapsible element with smooth expand/collapse animations for accordions and disclosure widgets.

The a-expandable element creates collapsible content sections with smooth CSS Grid-based animations. It handles accessibility automatically, including ARIA attributes, keyboard navigation, and anchor link support.

However, pigs have begun to rent cranberries over the past few months, specifically for chimpanzees associated with their dolphins. However, kiwis have begun to rent octopus over the past few months, specifically for prunes associated with their pigs. However, currants have begun to rent pears over the past few months, specifically for apricots associated with their dolphins! Far from the truth, however, chickens have begun to rent dogs over the past few months, specifically for snails associated with their zebras.

Used by Accordion, Combobox, Filter, and Select.

Installation

import "@atrium-ui/elements/expandable";

Usage

Basic Usage

<a-expandable>
  <button slot="toggle" type="button">
    Click to expand
  </button>
  <div>
    Hidden content that will be revealed
  </div>
</a-expandable>

Hidden content that will be revealed

Initially Opened

<a-expandable opened>
  <button slot="toggle" type="button">
    This starts open
  </button>
  <div>
    Visible content
  </div>
</a-expandable>

Visible content

Expand up

However, apples have begun to rent eagles over the past few months, specifically for pineapples associated with their dogs? However, crocodiles have begun to rent apricots over the past few months, specifically for puppies associated with their owls. However, prunes have begun to rent bananas over the past few months, specifically for pears associated with their currants. Far from the truth, however, persimmons have begun to rent kangaroos over the past few months, specifically for kangaroos associated with their monkeys.

Expand a Paragraph

It's an undeniable fact, really; however, blackberries have begun to rent cats over the past few months, specifically for apricots associated with their dogs. However, scorpions have begun to rent monkeys over the past few months, specifically for seals associated with their elephants? However, birds have begun to rent pandas over the past few months, specifically for goats associated with their melons; However, zebras have begun to rent peaches over the past few months, specifically for pandas associated with their giraffes.

However, hippopotamus have begun to rent kangaroos over the past few months, specifically for currants associated with their birds. However, owls have begun to rent chickens over the past few months, specifically for ducks associated with their blueberries. However, oranges have begun to rent tigers over the past few months, specifically for octopus associated with their kiwis. However, camels have begun to rent octopus over the past few months, specifically for bananas associated with their pigs.

Programmatic Control

const expandable = document.querySelector('a-expandable');

// Open the expandable
expandable.open();

// Close the expandable
expandable.close();

// Toggle the state
expandable.toggle();

// Check current state
if (expandable.opened) {
  console.log('Currently expanded');
}

Listening for Changes

const expandable = document.querySelector('a-expandable');

expandable.addEventListener('change', (event) => {
  console.log('Expanded:', event.target.opened);
});

Styling

The expandable uses CSS Grid for smooth height animations. Customise timing with CSS custom properties:

a-expandable {
  --transition-speed: 0.33s;
  --animation-easing: ease;
}

/* Faster animation */
a-expandable.fast {
  --transition-speed: 0.15s;
}

/* Slower, more dramatic */
a-expandable.slow {
  --transition-speed: 0.5s;
  --animation-easing: cubic-bezier(0.4, 0, 0.2, 1);
}

Styling the Toggle

a-expandable [slot="toggle"] {
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Rotate icon when opened */
a-expandable[opened] [slot="toggle"] .icon {
  transform: rotate(180deg);
}

Accessibility

  • ARIA Attributes: Automatically sets aria-expanded on the toggle and aria-labelledby on the content region.
  • Keyboard Support: Toggle responds to Enter and Space keys when focused.
  • Focus Management: Focusable elements inside collapsed content are removed from tab order.
  • Anchor Links: When a URL hash matches an element inside the expandable, it automatically opens to reveal the content.
  • Scroll Into View: When opened or closed, the expandable scrolls into view to prevent content from shifting off-screen.
  • Hidden Until Found: Uses hidden="until-found" for browser find-in-page support (where available).

CSS Custom Properties

PropertyDefaultDescription
--transition-speed0.33sDuration of the expand/collapse animation
--animation-easingeaseEasing function for the animation

Expandable

A element that can collapse and expand its content with an animation.

Example

<a-expandable opened class="accordion">
   <button slot="toggle" type="button">
     <div class="headline">Title</div>
   </button>

   <div>Content</div>
 </a-expandable>

Attributes

Name Type Default value Description
direction undefined undefined

What direction to open
opened undefined undefined

Wether the eleemnt is open or not

Events

Name Description
change

Emitted when the element open state changes

Methods

Expandable.close()

src/Expandable.ts:100

Expandable.open()

src/Expandable.ts:105

Expandable.toggle()

src/Expandable.ts:110

References