## API ### Collapse | Property | Description | Type | Default | | -------- | ----------- | ---- | ------- | | activeKey | Key of the active panel | string\[]\|string | No default value. In `accordion` mode, it's the key of the first panel. | | defaultActiveKey | Key of the initial active panel | string | - | | change | Callback function executed when active panel is changed | Function | - | ### Collapse.Panel | Property | Description | Type | Default | | -------- | ----------- | ---- | ------- | | disabled | If `true`, panel cannot be opened or closed | boolean | `false` | | header | Title of the panel | string | - | | key | Unique key identifying the panel from among its siblings | string | - | | showArrow | If `false`, panel will not show arrow icon | boolean | `true` |