Resizable panels animated with Motion. A framework-agnostic core with a React adapter, unstyled, and with no layout library underneath.

Think react-resizable-panels, except the folding, collapsing and snapping are real animations — and the resizing engine is plain DOM, so other frameworks can sit on top of it.

pnpm add motion-panels motion       # the core alone
pnpm add motion-panels motion react # with the React adapter

Or through shadcn, which writes a styled separator over the same components into components/ui/motion-panels.tsx:

npx shadcn@latest add https://motion-panels.letstri.dev/r/motion-panels.json

import { Group, Panel, Separator } from 'motion-panels/react'
import { useState } from 'react'

function Layout() {
  const [size, setSize] = useState(280)

  return (
    <Group orientation="horizontal">
      <Panel minSize={200} maxSize={480} size={size} onSizeChange={setSize}>
        <Sidebar />
      </Panel>
      <Separator />
      <Panel>
        <Content />
      </Panel>
    </Group>
  )
}

Space the panels with padding, a flex gap on the group (it opens on both sides of a separator), or not at all: the room a panel may take is measured, never assumed from the group extent. Every size is pixels or a percentage of the group — useState<Size>('30%') gives a panel that follows the group as it resizes, and onSizeChange reports back in whichever form it was given.

Folding, collapsing, pinning, nesting, reordering, separator intersections, keyboard and RTL support, plus the framework-agnostic core API — all with live demos:

motion-panels.letstri.dev

MIT © Valerii Strilets