# PagedCollection
A renderless component to act as a helper for different types of pagination.
```hbs preview-template
<figure>
<figcaption>
Provide a widget so we can try switching between two pagination methods
</figcaption>
<select
onchange={{action (mut this.type) value="target.value"}}
>
<option>virtual-scroll</option>
<option>index</option>
</select>
</figure>
<figure>
<figcaption>Get some data and page it</figcaption>
<DataSource
@src={{uri "/partition/default/dc-1/nodes"}}
as |source|>
<PagedCollection
@type={{or this.type "virtual-scroll"}}
@items={{or source.data (array)}}
@perPage={{8}}
@page={{or this.page 1}}
@rowHeight="43"
as |pager|>
<div
style={{{style-map
(array 'outline' '1px solid var(--token-color-palette-neutral-300)')
(array 'max-height' '360' 'px')
(array '--paged-row-height' (if (not-eq this.type 'index') '43px'))
}}}
{{did-insert pager.viewport}}
{{on-resize pager.resize}}
>
<ul
style={{{style-map
(array 'height' pager.totalHeight 'px')
(array '--paged-start' pager.startHeight 'px')
}}}
>
{{#each pager.items as |item|}}
<li
style={{{style-map
(array 'height' '43' 'px')
(array 'outline' '1px solid var(--token-color-surface-strong)')
}}}
>
{{item.Node}}
</li>
{{/each}}
</ul>
</div>
<pager.Pager>
<div
style={{{style-map
(array 'display' 'flex')
(array 'flex-direction' (if (not-eq pager.page pager.totalPages) 'row-reverse'))
(array 'justify-content' 'space-between')
}}}
>
{{#if (not-eq pager.page pager.totalPages)}}
<Action
{{on 'click' (set this 'page' (add pager.page 1))}}
>
Next
</Action>
{{/if}}
{{#if (not-eq pager.page 1)}}
<Action
{{on 'click' (set this 'page' (sub pager.page 1))}}
>
Prev
</Action>
{{/if}}
</div>
</pager.Pager>
</PagedCollection>
</DataSource>
</figure>
```
## Arguments
| Argument | Type | Default | Description |
| --- | --- | --- | --- |
| `type` | `(native-scroll \| virtual-scroll \| index)` | `native-scroll` | The type of pagination |
| `items` | `array` | `undefined` | An array or items to be paginated |
| `rowHeight` | `(string \| number)` | `undefined` | When `@type=virtual-scroll` this informs the scroller of the size of each row in the scroll pane. For the moment this _must_ be the same for every row. |
| `page` | `number` | `undefined` | When `@type=index` this is the current page number to show |
| `perPage` | `number` | `undefined` | When `@type=index` this is the amount of rows to show per page |
## Exported API
| Name | Type | Description |
| --- | --- | --- |
| `items` | `array` | An array of the items to be shown on the current page |
| `page` | `number` | The current page number (a mirror of @page) |
| `resize` | `Function` | Function to be called on the resize of the viewport |
| `viewport` | `Function` | Function to be called on the `did-insert` of the viewport to be used for scrolling |
| `rowHeight` | `Function` | Function to be called to set the rowHeight of the virtual-scroller |
| `startHeight` | `number` | Size of the area before the panel to be virtually-scroller, usually you should use this to set `--paged-start` wrapping element of the scrollable items |
| `totalHeight` | `number` | Size of the of the entire panel in order to show the correctly sized scroll thumb |
| `totalPages` | `number` | Totol number of pages |
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