useMotiPressables()

import { useMotiPressables } from 'moti/interactions'

useMotiPressables lets you access the interaction state of multiple MotiPressable parents. This lets you combine multiple different interactions and build animation states with ease.

Usage#

const ListItem = ({ id }) => {
  const state = useMotiPressables((containers) => {
    'worklet'

    // access items by their unique IDs
    const list = containers.list.value
    const item = containers[`item-${id}`].value

    let opacity = 1

    if (list.hovered && !item.hovered) {
      opacity = 0.5
    }

    return {
      opacity,
    }
  }, [])
}

return <MotiView state={state} />

Walk Through#

Imagine we have a list. The outer container component is a MotiPressable, and each item has a MotiPressable too.

<MotiPressable id="list">
  {items.map(id =>
    <MotiPressable id={`item-${id}`} key={id}>
      <ListItem id={id} />
    </MotiPressable>
  )}
<MotiPressable>

Now, the ListItem component can call useMotiPressables instead of useMotiPressable.

Say we want to make all items fade away when you hover over the list, except for the actual item you're hovering.

import { useMotiPressables } from 'moti/interactions'

const ListItem = ({ id }) => {
  const state = useMotiPressables((containers) => {
    'worklet'

    // access items by their unique IDs
    const list = containers.list.value
    const item = containers[`item-${id}`].value

    let opacity = 1

    if (list.hovered && !item.hovered) {
      opacity = 0.5
    }

    return {
      opacity,
    }
  }, [])
  return <MotiView state={state} />
}

Performance#

This hook runs on the native thread and triggers zero re-renders. Like all things moti, it has great performance out-of-the-box.

Similar to useMemo, you can also pass in a dependency array as the last argument to reduce updates:

const state = useMotiPressables(
  (containers) => {
    'worklet'

    const list = containers.list.value

    return {
      opacity: list.pressed && !loading ? 0.5 : 1,
    }
  },
  [loading] // pass an empty array if there are no dependencies
)

API#

The following usages are valid:

useMotiPressables(factory, deps?)

Arguments#

factory is a worklet that returns a style object.
- Its only argument is a containers dictionary, whose keys are the id props of the containers, and the values are the derived values of each interaction state.
id is a unique string to identify the parent MotiPressable component whose interaction state you're trying to access.
deps is a dependency array, just like useMemo

Returns#

A Moti state object, meant to be passed to any Moti component's state prop.