in components/RuiExpandCollapse/src/RuiExpandCollapse.ts [202:216]
public firstUpdated(): void {
if (this.shadowRoot) {
this._buttonEl = this.shadowRoot.querySelector('button') || undefined;
this._detailsSlotEl = this.shadowRoot.querySelector('#details-slot') as HTMLSlotElement || undefined;
if (this._detailsSlotEl) {
// when the slotted content changes we initialise expand collapse
// we need to wait for this because the animation of height calc
// will only work once the slot and it's content have mounted and rendered
this._detailsSlotEl.addEventListener('slotchange', (): void => {
this._initialiseExpandCollapse();
});
}
}
}