# Splitter

- Page: https://jiguang132.com/resources/mantine/docs/splitter
- Resource: Mantine Core (https://jiguang132.com/resources/mantine.md)
- All guides: https://jiguang132.com/resources/mantine/docs.md

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

```tsx
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](/hooks/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:

```tsx
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`.

```tsx
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](/hooks/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.


```ts
Splitter(_props)
```



```ts
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.


```ts
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
```

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