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import {Layout} from '@react-spectrum/docs'; export default Layout;

import docs from 'docs:@react-stately/data'; import {HeaderInfo, TypeContext, ClassAPI, FunctionAPI, TypeLink, PageDescription} from '@react-spectrum/docs'; import packageData from '@react-stately/data/package.json';

category: Data keywords: [lists, insert, remove, state]

useListData

<PageDescription>{docs.exports.useListData.description}</PageDescription>

<HeaderInfo packageData={packageData} componentNames={['useListData']} />

Introduction

React requires all data structures passed as props to be immutable. This enables them to be diffed correctly to determine what has changed since the last render. This can be challenging to accomplish from scratch in a performant way in JavaScript.

useListData helps manage an immutable list data structure, with helper methods to update the data in an efficient way. Since the data is stored in React state, calling these methods to update the data automatically causes the component to re-render accordingly.

In addition, useListData stores selection state for the list, based on unique item keys. This can be updated programmatically, and is automatically updated when items are removed from the list.

API

Options

Interface

Example

To construct a list, pass an initial set of items along with a function to get a key for each item. You can use the state returned by useListData to render a collection component.

This example renders a ListBox using the items managed by useListData. It uses the name property of each item as the unique key for that item, and the items property as the children. In addition, it manages the selection state for the listbox, which will automatically be updated when items are removed from the tree.

let list = useListData({
  initialItems: [
    {name: 'Aardvark'},
    {name: 'Kangaroo'},
    {name: 'Snake'}
  ],
  initialSelectedKeys: ['Kangaroo'],
  getKey: item => item.name
});

<ListBox
  items={list.items}
  selectedKeys={list.selectedKeys}
  onSelectionChange={list.setSelectedKeys}>
  {item => <Item key={item.name}>{item.name}</Item>}
</ListBox>

Inserting items

To insert a new item into the list, use the insert method or one of the other convenience methods. Each of these methods also accepts multiple items, so you can insert multiple items at once.

// Insert an item after the first one
list.insert(1, {name: 'Horse'});

// Insert multiple items
list.insert(1, {name: 'Horse'}, {name: 'Giraffe'});

// Insert an item before another item
list.insertBefore('Kangaroo', {name: 'Horse'});

// Insert multiple items before another item
list.insertBefore('Kangaroo', {name: 'Horse'}, {name: 'Giraffe'});

// Insert an item after another item
list.insertAfter('Kangaroo', {name: 'Horse'});

// Insert multiple items after another item
list.insertAfter('Kangaroo', {name: 'Horse'}, {name: 'Giraffe'});

// Append an item
list.append({name: 'Horse'});

// Append multiple items
list.append({name: 'Horse'}, {name: 'Giraffe'});

// Prepend an item
list.prepend({name: 'Horse'});

// Prepend multiple items
list.prepend({name: 'Horse'}, {name: 'Giraffe'});

Removing items

// Remove an item
list.remove('Kangaroo');

// Remove multiple items
list.remove('Kangaroo', 'Snake');

// Remove all selected items
list.removeSelectedItems();

Moving items

list.move('Snake', 0);

Updating items

list.update('Snake', {name: 'Rattle Snake'});