virtualized-list

A tiny vanilla virtualization library, with DOM diffing

Installation

Using npm:

npm install virtualized-list --save

Usage

Basic example

const rows = ['a', 'b', 'c', 'd'];

const virtualizedList = new VirtualizedList(container, {
  height: 500, // The height of the container
  rowCount: rows.length,
  renderRow: index => {
  	const element = document.createElement('div');
  	element.innerHTML = rows[index];

  	return element;
  },
  rowHeight: 150,
)};

Advanced example

const rows = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
const rowHeights = [150, 120, 100, 80, 50, 35, 200, 500, 50, 300];

const virtualizedList = new VirtualizedList(container, {
  height: 400,
  rowCount: rows.length,
  renderRow: (row, index) => {
  	const element = document.createElement('div');
  	element.innerHTML = row;

  	return element;
  },
  rowHeight: index => rowHeights[index],
  estimatedRowHeight: 155,
  overscanCount: 5, // Number of rows to render above/below the visible rows.
  initialScrollIndex: 8,
  onMount: () => {
    // Programatically scroll to item index #3 after 2 seconds
    setTimeout(() =>
      virtualizedList.scrollToIndex(3)
    , 2000);
  }
)}

Options

| Property | Type | Required? | Description | |:-------------------|:--------------------------|:----------|:----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | height | Number | ✓ | Height of List. This property will determine the number of rendered vs virtualized items | | rowCount | Number | ✓ | The number of rows you want to render | | renderRow | Function | ✓ | Responsible for rendering an item given it's index: ({index: number, style: Object}): React.PropTypes.node. The returned element must handle key and style. | | rowHeight | Number, Array or Function | ✓ | Either a fixed height, an array containing the heights of all the items in your list, or a function that returns the height of an item given its index: (index: number): number | | initialScrollTop | Number | | The initial scrollTop value (optional) | | initialIndex | Number | | Initial item index to scroll to (by forcefully scrolling if necessary) | | overscanCount | Number | | Number of extra buffer items to render above/below the visible items. Tweaking this can help reduce scroll flickering on certain browsers/devices. Defaults to 3 | | estimatedRowHeight | Number | | Used to estimate the total size of the list before all of its items have actually been measured. The estimated total height is progressively adjusted as items are rendered. | | onMount | Function | | Callback invoked once the virtual list has mounted. | | onScroll | Function | | Callback invoked onScroll. function (scrollTop, event) | | onRowsRendered | Function | | Callback invoked with information about the range of rows just rendered |