# 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 |


