@superhuman/react-list

ReactList

A versatile infinite scroll React component.

Install

bower install react-list

# or

npm install react-list

ReactList depends on React.

Examples

Check out the example page and the the example page source for examples of different configurations.

Here's another simple example to get you started.

import loadAccount from 'my-account-loader';
import React from 'react';
import ReactList from 'react-list';

class MyComponent extends React.Component {
  state = {
    accounts: []
  };

  componentWillMount() {
    loadAccounts(::this.handleAccounts);
  }

  handleAccounts(accounts) {
    this.setState({accounts});
  }

  renderItem(index, key) {
    return <div key={key}>{this.state.accounts[index].name}</div>;
  }

  render() {
    return (
      <div>
        <h1>Accounts</h1>
        <div style={{overflow: 'auto', maxHeight: 400}}>
          <ReactList
            itemRenderer={::this.renderItem}
            length={this.state.accounts.length}
            type='uniform'
          />
        </div>
      </div>
    );
  }
}

Props

axis (defaults to y)

The axis that this list scrolls on.

initialIndex

An index to scroll to after mounting.

itemRenderer(index, key)

A function that receives an index and a key and returns the content to be rendered for the item at that index.

itemsRenderer(items, ref)

A function that receives the rendered items and a ref. By default this element is just a <div>. Generally it only needs to be overridden for use in a <table> or other special case. NOTE: You must set ref={ref} on the component that contains the items so the correct item sizing calculations can be made.

itemSizeEstimator(index, cache)

A function that receives an item index and the cached known item sizes and returns an estimated size (height for y-axis lists and width for x-axis lists) of that item at that index. This prop is only used when the prop type is set to variable and itemSizeGetter is not defined. Use this property when you can't know the exact size of an item before rendering it, but want it to take up space in the list regardless.

itemSizeGetter(index)

A function that receives an item index and returns the size (height for y-axis lists and width for x-axis lists) of that item at that index. This prop is only used when the prop type is set to variable.

length (defaults to 0)

The number of items in the list.

minSize (defaults to 1)

The minimum number of items to render at any given time. This can be used to render some amount of items initially when rendering HTML on the server.

pageSize (defaults to 10)

The number of items to batch up for new renders. Does not apply to 'uniform' lists as the optimal number of items is calculated automatically.

scrollParentGetter (defaults to finding the nearest scrollable parent)

A function that returns a DOM Element or Window that will be treated as the scrolling container for the list. In most cases this does not need to be set for the list to work as intended. It is exposed as a prop for more complicated uses where the scrolling container may not initially have an overflow property that enables scrolling.

scrollParentViewportSizeGetter (defaults to scrollParent's viewport size)

A function that returns the size of the scrollParent's viewport. Provide this prop if you can efficiently determine your scrollParent's viewport size as it can improve performance.

threshold (defaults to 100)

The number of pixels to buffer at the beginning and end of the rendered list items.

type (one of simple, variable, or uniform, defaults to simple)

• simple This type is...simple. It will not cache item sizes or remove items that are above the viewport. This type is sufficient for many cases when the only requirement is incremental rendering when scrolling.

• variable This type is preferred when the sizes of the items in the list vary. Supply the itemSizeGetter when possible so the entire length of the list can be established beforehand. Otherwise, the item sizes will be cached as they are rendered so that items that are above the viewport can be removed as the list is scrolled.

• uniform This type is preferred when you can guarantee all of your elements will be the same size. The advantage here is that the size of the entire list can be calculated ahead of time and only enough items to fill the viewport ever need to be drawn. The size of the first item will be used to infer the size of every other item. Multiple items per row are also supported with this type.

useStaticSize (defaults to false)

Set to true if the item size will never change (as a result of responsive layout changing or otherwise). This prop is only used when the prop type is set to uniform. This is an opt-in optimization that will cause the very first element's size to be used for all elements for the duration of the component's life.

useTranslate3d (defaults to false)

A boolean to determine whether the translate3d CSS property should be used for positioning instead of the default translate. This can help performance on mobile devices, but is supported by fewer browsers.

Methods

scrollTo(index)

Put the element at index at the top of the viewport. Note that if you aren't using type='uniform' or an itemSizeGetter, you will only be able to scroll to an element that has already been rendered.

scrollAround(index)

Scroll the viewport so that the element at index is visible, but not necessarily at the top. The scrollTo note above also applies to this method.

getVisibleRange() => [firstIndex, lastIndex]

Return the indices of the first and last items that are at all visible in the viewport.

FAQ

What is "ReactList failed to reach a stable state."?

This happens when specifying the uniform type without actually providing uniform size elements. The component attempts to draw only the minimum necessary elements at one time and that minimum element calculation is based off the first element in the list. When the first element does not match the other elements, the calculation will be wrong and the component will never be able to fully resolve the ideal necessary elements.

Why doesn't it work with margins?

The calculations to figure out element positioning and size get significantly more complicated with margins, so they are not supported. Use a transparent border or padding or an element with nested elements to achieve the desired spacing.

Why is there no onScroll event handler?

If you need an onScroll handler, just add the handler to the div wrapping your ReactList component:

<div style={{height: 300, overflow: 'auto'}} onScroll={this.handleScroll}>
  <ReactList ... />
</div>

Development

open docs/index.html
make