Collection.md

Collection

Renders scattered or non-linear data. Unlike Grid, which renders checkerboard data, Collection can render arbitrarily positioned- even overlapping- data.

Note that this component's measuring and layout phase is more expensive than Grid since it can not assume a correlation between a cell's index and position. For this reason it will take significantly longer to initialize than the more linear/checkerboard components.

Prop Types

Property	Type	Required?	Description
autoHeight	Boolean		Outer height of Collection is set to "auto". This property should only be used in conjunction with the WindowScroller HOC.
className	String		Optional custom CSS class name to attach to root Collection element.
cellCount	Number	✓	Number of cells in collection.
cellGroupRenderer	Function		Responsible for rendering a group of cells given their indices.: ({ cellSizeAndPositionGetter:Function, indices: Array<number>, cellRenderer: Function }): Array<PropTypes.node>
cellRenderer	Function	✓	Responsible for rendering a cell given an row and column index: ({ index: number, isScrolling: boolean, key: string, style: object }): PropTypes.element
cellSizeAndPositionGetter	Function	✓	Callback responsible for returning size and offset/position information for a given cell (index): ({ index: number }): { height: number, width: number, x: number, y: number }
height	Number	✓	Height of Collection; this property determines the number of visible (vs virtualized) rows.
horizontalOverscanSize	Number		Enables the Collection to horizontally "overscan" its content similar to how Grid does. This can reduce flicker around the edges when a user scrolls quickly. This property defaults to 0;
id	String		Optional custom id to attach to root Collection element.
noContentRenderer	Function		Optional renderer to be rendered inside the grid when cellCount is 0: (): PropTypes.node
onSectionRendered	Function		Callback invoked with information about the section of the Collection that was just rendered: ({ indices: Array<number> }): void
onScroll	Function		Callback invoked whenever the scroll offset changes within the inner scrollable region: ({ clientHeight: number, clientWidth: number, scrollHeight: number, scrollLeft: number, scrollTop: number, scrollWidth: number }): void
scrollLeft	Number		Horizontal offset
scrollToAlignment	String		Controls the alignment of scrolled-to-cells. The default ("auto") scrolls the least amount possible to ensure that the specified cell is fully visible. Use "start" to always align cells to the top/left of the Collection and "end" to align them bottom/right. Use "center" to align specified cell in the middle of container.
scrollToCell	Number		Cell index to ensure visible (by scrolling if necessary)
scrollTop	Number		Vertical offset
sectionSize	Number		Optionally override the size of the sections a Collection's cells are split into. This is an advanced option and should only be used for performance tuning purposes.
style	Object		Optional custom inline style to attach to root Collection element.
verticalOverscanSize	Number		Enables the Collection to vertically "overscan" its content similar to how Grid does. This can reduce flicker around the edges when a user scrolls quickly. This property defaults to 0;
width	Number	✓	Width of Collection; this property determines the number of visible (vs virtualized) columns.

Public Methods

recomputeCellSizesAndPositions

Recomputes cell sizes and positions.

This function should be called if cell sizes or positions have changed but nothing else has. Since Collection only receives cellCount (and not the underlying List or Array) it has no way of detecting when the underlying data changes.

Class names

The Collection component supports the following static class names

Property	Description
ReactVirtualized__Collection	Main (outer) element
ReactVirtualizedCollectioninnerScrollContainer	Inner scrollable area

Examples

Below is a very basic Collection example. It displays an array of objects with fixed row and column sizes. See here for a more full-featured example.

import React from 'react';
import ReactDOM from 'react-dom';
import {Collection} from 'react-virtualized';
import 'react-virtualized/styles.css'; // only needs to be imported once

// Collection data as an array of objects
const list = [
  {name: 'Brian Vaughn', x: 13, y: 34, width: 123, height: 234},
  // And so on...
];

function cellRenderer({index, key, style}) {
  return (
    <div key={key} style={style}>
      {list[index].name}
    </div>
  );
}

function cellSizeAndPositionGetter({index}) {
  const datum = list[index];

  return {
    height: datum.height,
    width: datum.width,
    x: datum.x,
    y: datum.y,
  };
}

// Render your grid
ReactDOM.render(
  <Collection
    cellCount={list.length}
    cellRenderer={cellRenderer}
    cellSizeAndPositionGetter={cellSizeAndPositionGetter}
    height={300}
    width={300}
  />,
  document.getElementById('example'),
);