ResizablePanels

Files

README.md
theme.css
App.tsx

Editor

Focus the divider and use the arrow keys.

Usage

import { ResizablePanels } from "@devvy-ui/react";

<ResizablePanels label="Resize editor">{[<p key="a">Files</p>,<p key="b">Editor</p>]}</ResizablePanels>

API reference

Native HTML attributes, className, style and a forwarded ref are supported. Component-specific props:

Prop	Type	Default	Description
children	readonly [ReactNode, ReactNode]	required	The two panel contents.
value / defaultValue	number	50	First-panel percentage.
min / max	number	10 / 90	Allowed split.
orientation	horizontal / vertical	horizontal	Panel direction.

Source ownership

Run npx @devvy-ui/cli init once in your React project, then add the source:

npx @devvy-ui/cli add resizable-panels

Make the source yours.

Start from the canonical implementation used by the package and registry. Change the code, keep the MIT notice, and build the behavior your project needs.

ResizablePanels.tsxREACT / TSX

/* eslint-disable jsx-a11y/no-noninteractive-element-interactions, jsx-a11y/no-noninteractive-tabindex -- The ARIA window-splitter pattern requires a focusable separator with range values and keyboard/pointer handling. */
import { forwardRef, useRef, type HTMLAttributes, type ReactNode } from 'react';
import { useValue } from '../lib/widgets';
export interface ResizablePanelsProps
  extends Omit<HTMLAttributes<HTMLDivElement>, 'children' | 'defaultValue' | 'onChange'> {
  label: string;
  children: readonly [ReactNode, ReactNode];
  value?: number;
  defaultValue?: number;
  onValueChange?: (percent: number) => void;
  min?: number;
  max?: number;
  orientation?: 'horizontal' | 'vertical';
}
export const ResizablePanels = forwardRef<HTMLDivElement, ResizablePanelsProps>(
  function ResizablePanels(
    {
      label,
      children,
      value,
      defaultValue = 50,
      onValueChange,
      min = 10,
      max = 90,
      orientation = 'horizontal',
      className,
      ...props
    },
    ref,
  ) {
    const [raw, setRaw] = useValue(value, defaultValue, onValueChange),
      root = useRef<HTMLDivElement>(null);
    const lower = Math.max(0, Math.min(99, Number.isFinite(min) ? min : 10)),
      upper = Math.max(lower + 1, Math.min(100, Number.isFinite(max) ? max : 90)),
      percent = Math.max(lower, Math.min(upper, Number.isFinite(raw) ? raw : 50));
    const update = (next: number) => setRaw(Math.max(lower, Math.min(upper, next)));
    return (
      <div
        {...props}
        ref={(node) => {
          root.current = node;
          if (typeof ref === 'function') ref(node);
          else if (ref) ref.current = node;
        }}
        className={['dvy-resizable-panels', className].filter(Boolean).join(' ')}
        data-orientation={orientation}
      >
        <div style={{ flexBasis: percent + '%' }}>{children[0]}</div>
        <div
          role="separator"
          tabIndex={0}
          aria-label={label}
          aria-orientation={orientation === 'horizontal' ? 'vertical' : 'horizontal'}
          aria-valuemin={lower}
          aria-valuemax={upper}
          aria-valuenow={Math.round(percent)}
          className="dvy-resize-handle"
          onKeyDown={(event) => {
            const rtl = getComputedStyle(event.currentTarget).direction === 'rtl';
            const forward =
                orientation === 'vertical' ? 'ArrowDown' : rtl ? 'ArrowLeft' : 'ArrowRight',
              back = orientation === 'vertical' ? 'ArrowUp' : rtl ? 'ArrowRight' : 'ArrowLeft';
            if ([forward, back, 'Home', 'End'].includes(event.key)) {
              event.preventDefault();
              update(
                event.key === 'Home'
                  ? lower
                  : event.key === 'End'
                    ? upper
                    : percent + (event.key === forward ? 1 : -1) * (event.shiftKey ? 10 : 1),
              );
            }
          }}
          onPointerDown={(event) => event.currentTarget.setPointerCapture(event.pointerId)}
          onPointerMove={(event) => {
            if (!event.currentTarget.hasPointerCapture(event.pointerId)) return;
            const bounds = root.current!.getBoundingClientRect(),
              rtl = getComputedStyle(event.currentTarget).direction === 'rtl';
            const ratio =
              orientation === 'vertical'
                ? (event.clientY - bounds.top) / bounds.height
                : rtl
                  ? (bounds.right - event.clientX) / bounds.width
                  : (event.clientX - bounds.left) / bounds.width;
            update(ratio * 100);
          }}
          onPointerUp={(event) => {
            if (event.currentTarget.hasPointerCapture(event.pointerId))
              event.currentTarget.releasePointerCapture(event.pointerId);
          }}
        />
        <div>{children[1]}</div>
      </div>
    );
  },
);

Edit your own copy. Downloaded source uses your changes; the component preview above uses the shipped version. Run the source installer first to include shared helpers.

Interactive preview

Usage

API reference

Accessibility & behavior

Platform Behavior & Guidelines

Source ownership

Make the source yours.