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Collapsible: Examples

Custom Invoker Template

A custom template can be specified to the invoker slot. It can be any button or custom component which mimics the button behavior for better accessibility support. In the below example, lion-button and native button with styling is used as a collapsible invoker.

export const customInvokerTemplate = () => html`
  <lion-collapsible style="margin-top:16px;">
    <lion-button slot="invoker">More about cars</lion-button>
    <div slot="content">
      Most definitions of cars say that they run primarily on roads, seat one to eight people, have
      four tires, and mainly transport people rather than goods.
    </div>
  </lion-collapsible>
`;

Extended collapsible with animation

LionCollapsible can easily be extended to add more features in the component, like animation for example.

export const customAnimation = () => html`
  <div class="demo-custom-collapsible-container">
    <div class="demo-custom-collapsible-body">
      A motorcycle, often called a motorbike, bike, or cycle, is a two- or three-wheeled motor
      vehicle.
    </div>
    <custom-collapsible>
      <button class="demo-custom-collapsible-invoker" slot="invoker">MORE ABOUT MOTORCYCLES</button>
      <div slot="content">
        Motorcycle design varies greatly to suit a range of different purposes: long distance
        travel, commuting, cruising, sport including racing, and off-road riding. Motorcycling is
        riding a motorcycle and related social activity such as joining a motorcycle club and
        attending motorcycle rallies.
      </div>
    </custom-collapsible>
  </div>
  <div class="demo-custom-collapsible-container">
    <div class="demo-custom-collapsible-body">
      A car (or automobile) is a wheeled motor vehicle used for transportation.
    </div>
    <custom-collapsible opened>
      <button class="demo-custom-collapsible-invoker" slot="invoker">MORE ABOUT CARS</button>
      <div slot="content">
        Most definitions of cars say that they run primarily on roads, seat one to eight people,
        have four tires, and mainly transport people rather than goods.
      </div>
    </custom-collapsible>
  </div>
`;

Use _showAnimation() and _hideAnimation() methods to customize open and close behavior. Check the code for a full example of a custom-collapsible.

_showAnimation({ contentNode }) {
    const expectedHeight = await this.__calculateHeight(contentNode);
    contentNode.style.setProperty('opacity', '1');
    contentNode.style.setProperty('padding', '12px 0');
    contentNode.style.setProperty('max-height', '0px');
    await new Promise(resolve => requestAnimationFrame(() => resolve()));
    contentNode.style.setProperty('max-height', expectedHeight);
    await this._waitForTransition({ contentNode });
}

_hideAnimation({ contentNode }) {
    if (this._contentHeight === '0px') {
      return;
    }
    ['opacity', 'padding', 'max-height'].map(prop => contentNode.style.setProperty(prop, 0));
    await this._waitForTransition({ contentNode });
}