# ResizablePanelGroup

> Two-or-more-panel layout with pointer and keyboard-accessible resize separators.

- Status: beta
- Group: layout
- Page: https://www.digitaltableteur.com/design-system/components/resizable-panel-group
- Contract: https://www.digitaltableteur.com/contracts/v1/ResizablePanelGroup.contract.json

## When to use

Use ResizablePanelGroup for adjacent work areas whose relative space users need to control. Set realistic minimum sizes for every panel.

## When not to use

- Do not replace a fixed responsive page grid.
- Do not allow panels to shrink below usable content minimums.

## Look-alikes

The contract names no look-alike with a deciding condition.

## Props

| Prop | Type | Default | Description | Required |
| --- | --- | --- | --- | --- |
| `panels` | `ResizablePanel[]` | none | Two or more ordered panels. | Yes |
| `orientation` | `"horizontal" \| "vertical"` | `horizontal` | Resize axis. | No |
| `keyboardStep` | `number` | `5` | Keyboard resize increment in percentage points. | No |
| `onSizesChange` | `(sizes: Record<string, number>) => void` | none | Receives the current percentage per panel id. | No |
| `className` | `string` | none | No description in the contract. | No |

## Variants

- Available orientations: `horizontal`, `vertical` (default `horizontal`).

## Invalid combinations

The contract records no invalid combinations.

## Keyboard

| Key | Behaviour |
| --- | --- |
| ArrowLeft | Moves focus or the value in that direction. (standard) |
| ArrowRight | Moves focus or the value in that direction. (standard) |
| ArrowUp | Moves focus or the value in that direction. (standard) |
| ArrowDown | Moves focus or the value in that direction. (standard) |
| Home | Moves to the first item. (standard) |
| End | Moves to the last item. (standard) |

Rows marked (standard) name a key the contract lists without a description; the behaviour shown is the usual one for that key.

## Rules

Every item under When not to use is a MUST NOT. MUST and SHOULD follow RFC 2119.

| Level | Rule | How it is checked |
| --- | --- | --- |
| MUST | ARIA: Each panel is a named region. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: Handles use role=separator. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: Separator exposes aria-orientation, aria-valuemin, aria-valuemax and aria-valuenow. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | Required stories produce no axe violations at the configured severity. | Automated by `npm run test:stories:matrix:ci`. WCAG 2.5.8. |
| MUST | The accessibility tree (role, name, state) matches the committed snapshot for every required story. | Automated by `npm run test:stories:matrix:ci`. WCAG 1.3.1, 4.1.2. |
| MUST | The component remains legible and operable under a real browser forced-colors: active pass. | Automated by `npm run test:stories:hc`. |
| MUST | Every documented keyboard interaction works as specified. | Not yet verified: no evidence record. WCAG 2.1.1, 2.1.2. |
| MUST | A human completed an end-to-end accessibility review of this component. | Manual review, last on 2026-07-26. |
| SHOULD | Name every panel region so assistive technology communicates its purpose. | Not stated in the contract. |
| SHOULD | Choose minimum sizes that keep each panel's essential controls usable. | Not stated in the contract. |
| SHOULD | Persist sizes only when restoring the user's workspace is genuinely valuable. | Not stated in the contract. |
| SHOULD | Use a keyboard step that changes layout perceptibly without large jumps. | Not stated in the contract. |
| SHOULD NOT | Do not replace an ordinary responsive page grid with draggable panels. | Not stated in the contract. |
| SHOULD NOT | Do not allow a panel to collapse past the minimum needed by its content. | Not stated in the contract. |

## Install and import

- Install: `npm install @digitaltableteur/react` (version 0.9.1, restricted access on npm).
- Import: `import { ResizablePanelGroup } from "@digitaltableteur/react";`
- Entry point: `@digitaltableteur/react/layout` exports it too.
- Styles: import `@digitaltableteur/react/style.css` once at the app boundary.

## Links

- Machine-readable contract (Design System Contract 1.0): https://www.digitaltableteur.com/contracts/v1/ResizablePanelGroup.contract.json
- Markdown version of this page: https://www.digitaltableteur.com/design-system/components/resizable-panel-group.md
- Component index as JSON: https://www.digitaltableteur.com/design-system/components.json
- All components: https://www.digitaltableteur.com/design-system/components
- Source: The implementation lives in a private repository. This page, its Markdown twin and the contract are generated from it at build time and are the public source of truth.