Splitter

Install: npm install @mantine/core@9.7.1 @mantine/hooks@9.7.1

Version and compatibility

Pinned Mantine Core 9.7.1 requires React and React DOM ^19.2.0 and matching @mantine/hooks@9.7.1, from the installed npm package's peerDependencies. Do not force it into React 18 or another incompatible version. Explain upgrade impact and agree on a plan with the project owner; do not hide conflicts with --force/--legacy-peer-deps. The native Provider enables theme.respectReducedMotion and uses forceColorScheme for light/dark.

Use case

Resize adjacent content panes.

Native props used by this example

These props are extracted from the local typechecked JSX and grouped by their owning native component. This is not an exhaustive prop list; see pinned source signatures and inheritance below.

Component prop	Explanation
`Splitter.style`	Local style/layout object.
`Splitter.Pane.defaultSize`	Initial splitter pane size.

Interaction and state checks

Current scenarios: Default. Check actual behavior after selecting supported disabled/error/read-only scenarios; components without those native states do not receive invented universal props. Verify keyboard focus and exits, then connect changed values through the native callback signature.

Business integration boundary

Demo content/state is local, without server persistence, authorization or fetching. A static display component is not a completed business workflow.

Host setup

Install pinned @mantine/core and @mantine/hooks, import @mantine/core/styles.css at the entry and use MantineProvider. The example's theme/variant are JGuang-authored host props, not universal native component APIs; forceColorScheme synchronizes the app theme. Native implementation source is a reading reference: use npm exports rather than copying internal engines. This batch covers Core, not dates/charts/forms extension packages. Detailed upstream prose remains English.

Runnable usage

import { useState } from 'react';
import * as M from '@mantine/core';
import '@mantine/core/styles.css';


function ComponentPreview({ variant = 'Default' }: { variant?: string }) {

return <M.Splitter style={{ width: 360, height: 200 }}><M.Splitter.Pane defaultSize="50%">Left</M.Splitter.Pane><M.Splitter.Pane defaultSize="50%">Right</M.Splitter.Pane></M.Splitter>;
}
export default function Example({ variant = 'Default', theme = 'light' }: { variant?: string; theme?: 'light' | 'dark' }) {
return <M.MantineProvider forceColorScheme={theme} theme={{ respectReducedMotion: true }}><ComponentPreview variant={variant} /></M.MantineProvider>;
}

Preview states

Default

The example uses the native Mantine API. For supported input demos, change the local variant to Disabled, Invalid or Read only; these are example labels, not new component props. Keep the documented data, controlled values, stores and compound children when adapting the example.

Usage

Splitter component provides resizable split pane layout. It is built on top of the use-splitter hook.

CSS units

Splitter.Pane defaultSize, min and max props accept CSS units in addition to plain numbers:

A plain number or a % string ('30%') is a flexible size – the pane shares the leftover space with other flexible panes.
A px or rem string ('240px', '15rem') is a fixed size – the pane keeps its pixel size when the container is resized and only changes when its own handle is dragged.

sizes and onSizeChange use the unit the pane was declared with: a '240px' pane stays '240px', a flexible pane reports a percentage. When the container is smaller than the sum of the fixed panes, fixed panes shrink proportionally.

Vertical orientation

Set orientation="vertical" to split panes vertically:

Collapsible panes

Set collapsible prop on Splitter.Pane to allow the pane to be collapsed by dragging past its minimum size. Use splitterRef to access imperative API for programmatic collapse/expand:

Controlled

To control panel sizes, use sizes and onSizeChange props:

Multiple panes

Splitter supports any number of panes. Handles are automatically rendered between panes:

Nested splitters

You can nest Splitter components to create complex layouts:

Redistribute

When using multiple panes, set redistribute prop to control how space is borrowed from non-adjacent panels when the immediate neighbor is at its min/max:

Line size

Use lineSize prop to control the thickness of the separator line between panes:

Without handle

Set withHandle={false} to hide the thumb with grip icon. The separator line between panes is still visible and draggable:

Imperative API

Use splitterRef prop to access imperative splitter API:

import { useRef } from 'react';
import { Splitter } from '@mantine/core';
import { UseSplitterReturnValue } from '@mantine/hooks';

function Demo() {
  const splitterRef = useRef<UseSplitterReturnValue>(null);

  return (
    <>
      <button onClick={() => splitterRef.current?.collapse(0)}>
        Collapse first pane
      </button>
      <Splitter splitterRef={splitterRef}>
        <Splitter.Pane defaultSize={50} min={20} collapsible>
          First pane
        </Splitter.Pane>
        <Splitter.Pane defaultSize={50} min={20}>
          Second pane
        </Splitter.Pane>
      </Splitter>
    </>
  );
}

Wrap Splitter.Pane

Splitter component relies on Splitter.Pane order. Wrapping Splitter.Pane is not supported, Splitter.Pane must be a direct child of Splitter.

import { Splitter } from '@mantine/core';

// This will not work – wrapped pane will not be recognized
function WillNotWork() {
  return (
    <Splitter.Pane defaultSize={50} min={20}>
      This part will not render correctly
    </Splitter.Pane>
  );
}

// Create a separate component for pane content instead
function PaneContent() {
  return <div>This will work as expected!</div>;
}

function Demo() {
  return (
    <Splitter h={200}>
      <Splitter.Pane defaultSize={50} min={20}>
        First pane
      </Splitter.Pane>
      {/* Do not wrap Splitter.Pane in another component */}
      {/* <WillNotWork /> */}
      <Splitter.Pane defaultSize={50} min={20}>
        <PaneContent />
      </Splitter.Pane>
    </Splitter>
  );
}

use-splitter hook

Splitter component is built on top of the use-splitter hook. If you need more control over the layout and styling, you can use the hook directly.

Source-backed parameter reference

Implementation signatures and types are generated from the pinned local source. Optional props, native inherited types, union branches and never exclusions are preserved. A forwardRef implementation's ref is a React reference, not an additional business prop.

Splitter(_props)

export type SplitterStylesNames = 'root' | 'handle' | 'thumb' | SplitterPaneStylesNames;

export type SplitterCssVariables = {
  root: '--splitter-line-size' | '--splitter-handle-color';
};

export interface SplitterProps
  extends BoxProps, StylesApiProps<SplitterFactory>, ElementProps<'div'> {
  /** Layout direction @default 'horizontal' */
  orientation?: 'horizontal' | 'vertical';

  /** Controlled sizes, each value keeps the unit it was declared in (number/`%` flexible, `px`/`rem` fixed) */
  sizes?: SplitterPaneSize[];

  /** Called during resize with updated sizes, each value keeps its declared unit */
  onSizeChange?: (sizes: SplitterPaneSize[]) => void;

  /** Called when drag starts */
  onResizeStart?: (handleIndex: number) => void;

  /** Called when drag ends */
  onResizeEnd?: (handleIndex: number, sizes: SplitterPaneSize[]) => void;

  /** Called when a panel collapses or expands */
  onCollapseChange?: (panelIndex: number, collapsed: boolean) => void;

  /** How to redistribute space when immediate neighbor is at its min/max */
  redistribute?: 'nearest' | 'equal' | UseSplitterRedistributeFn;

  /** Keyboard step size, a `number`/`%` is a percentage, `px`/`rem` is resolved to pixels @default 1 */
  step?: SplitterStep;

  /** Shift+arrow step size, a `number`/`%` is a percentage, `px`/`rem` is resolved to pixels @default 10 */
  shiftStep?: SplitterStep;

  /** CSS value for separator line thickness between panes @default 2 */
  lineSize?: number | string;

  /** Key of `theme.colors` or any valid CSS color for the separator line */
  handleColor?: MantineColor;

  /** Custom icon displayed in the handle thumb, by default uses grip icon based on orientation */
  handleIcon?: React.ReactNode;

  /** Determines whether the thumb with grip icon is displayed on the handle @default true */
  withHandle?: boolean;

  /** Restore the two panes adjacent to a handle to their default ratio (preserving their combined size) when the handle is double-clicked @default true */
  resetOnDoubleClick?: boolean;

  /** Ref to imperative splitter API (sizes, collapse, expand, etc.) */
  splitterRef?: React.RefObject<UseSplitterReturnValue | null>;

  /** Splitter panes */
  children?: React.ReactNode;
}

export type SplitterFactory = Factory<{
  props: SplitterProps;
  ref: HTMLDivElement;
  stylesNames: SplitterStylesNames;
  vars: SplitterCssVariables;
  staticComponents: {
    Pane: typeof SplitterPane;
  };
}>;

export type Mod = Record<string, any> | string;

export type BoxMod = Mod | Mod[] | BoxMod[];

export interface BoxProps extends MantineStyleProps {
  /** Class added to the root element, if applicable */
  className?: string | undefined;

  /** Inline style added to root component element, can subscribe to theme defined on MantineProvider */
  style?: MantineStyleProp;

  /** CSS variables defined on root component element */
  __vars?: CssVarsProp;

  /** `size` property passed down the HTML element */
  __size?: string;

  /** Breakpoint above which the component is hidden with `display: none` */
  hiddenFrom?: MantineBreakpoint;

  /** Breakpoint below which the component is hidden with `display: none` */
  visibleFrom?: MantineBreakpoint;

  /** Determines whether component should be hidden in light color scheme with `display: none` */
  lightHidden?: boolean;

  /** Determines whether component should be hidden in dark color scheme with `display: none` */
  darkHidden?: boolean;

  /** Element modifiers transformed into `data-` attributes, for example, `{ 'data-size': 'xl' }`, falsy values are removed */
  mod?: BoxMod;
}

export type ElementProps<
  ElementType extends React.ElementType,
  PropsToOmit extends string = never,
> = Omit<React.ComponentProps<ElementType>, 'style' | PropsToOmit>;

export interface CSSProperties extends React.CSSProperties {
  [key: string]: any;
}

type MantineStyle = CSSProperties | ((theme: MantineTheme) => CSSProperties);

export type MantineStyleProp = MantineStyle | MantineStyle[] | MantineStyleProp[] | undefined;

export type CssVariable = `--${string}`;

export type CssVariables<Variable extends string = CssVariable> = Partial<Record<Variable, string>>;

export type CssVars<Variable extends string = CssVariable> =
  | CssVariables<Variable>
  | ((theme: MantineTheme) => CssVariables<Variable>)
  | CssVars<Variable>[];

export type CssVarsProp<Variable extends string = CssVariable> =
  | CssVars<Variable>
  | CssVars<Variable>[];

Native and external types

External types remain defined by React or native dependencies, not manually expanded into guessed props. The installed version's TypeScript definitions are authoritative.

Factory<{
  props: SplitterProps;
  ref: HTMLDivElement;
  stylesNames: SplitterStylesNames;
  vars: SplitterCssVariables;
  staticComponents: {
    Pane: typeof SplitterPane;
  };
}>
MantineStyleProps
React.CSSProperties
MantineTheme
Partial<Record<Variable, string>>
Record<Variable, string>
Variable
MantineBreakpoint
Record<string, any>
StylesApiProps<SplitterFactory>
React.ElementType
Omit<React.ComponentProps<ElementType>, 'style' | PropsToOmit>
React.ComponentProps<ElementType>
ElementType
PropsToOmit
SplitterPaneSize
UseSplitterRedistributeFn
SplitterStep
MantineColor
React.ReactNode
React.RefObject<UseSplitterReturnValue | null>
UseSplitterReturnValue
HTMLDivElement
SplitterPaneStylesNames