LazyVStack

Expo UI LazyVStack matches the official SwiftUI LazyVStack API and arranges its children vertically, creating items only as needed (when they become visible during scrolling).

LazyVStack is not truly lazy yet: the native side only builds visible items, but React still creates every child up front, so large lists can be slow to mount. We are working on improving this. For large lists, we recommend FlashList or Legend List.

Usage

Basic lazy vertical stack

LazyVStack should be used inside a ScrollView to enable lazy rendering.

import {
  Host,
  ScrollView,
  LazyVStack,
  Text,
} from '@expo/ui/swift-ui';

export default function BasicLazyVStackExample() {
  return (
    <Host style={{ flex: 1 }}>
      <ScrollView>
        <LazyVStack spacing={12}>
          {Array.from({ length: 100 }, (_, i) => (
            <Text key={i}>{`Item ${i}`}</Text>
          ))}
        </LazyVStack>
      </ScrollView>
    </Host>
  );
}

With alignment

The alignment prop controls horizontal alignment of children. Available options are: leading, center, and trailing.

import {
  Host,
  ScrollView,
  LazyVStack,
  Rectangle,
} from '@expo/ui/swift-ui';
import { frame } from '@expo/ui/swift-ui/modifiers';

export default function LazyVStackAlignmentExample() {
  return (
    <Host
      matchContents={{ vertical: true }}
      style={{ width: '100%' }}>
      <ScrollView>
        <LazyVStack spacing={12} alignment="leading">
          <Rectangle
            modifiers={[frame({ width: 50, height: 50 })]}
          />
          <Rectangle
            modifiers={[frame({ width: 100, height: 50 })]}
          />
          <Rectangle
            modifiers={[frame({ width: 75, height: 50 })]}
          />
        </LazyVStack>
      </ScrollView>
    </Host>
  );
}

API

import { LazyVStack } from '@expo/ui/swift-ui';

Component

`LazyVStack`

Type: React.Element<LazyVStackProps>

LazyVStackProps

`alignment`

Optional • Literal type: string

The horizontal alignment of children within the stack.

Acceptable values are: 'center' | 'leading' | 'trailing'

`children`

Type: ReactNode

`spacing`

Optional • Type: number

The spacing between children.

Inherited props

CommonViewModifierProps

Modifiers

Use these modifiers in the modifiers prop of the SwiftUI version.

Modifiers for LazyVStack

scrollTargetLayout iOS 17+

Modifiers for any view

Sources

The original Expo docs for this page:

LazyVStack (SwiftUI) (source-of-truth/versions/v57.0.0/sdk/ui/swift-ui/lazyvstack.md)

On this page