Split Panel

<wa-split-panel>

Stable

Split panels display two adjacent panels separated by a draggable divider, letting users resize each side to suit their workflow.

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<wa-split-panel>
  <div
    slot="start"
    style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    Start
  </div>
  <div
    slot="end"
    style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    End
  </div>
</wa-split-panel>

Examples

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Initial Position

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To set the initial position, use the position attribute. If no position is provided, it will default to 50% of the available space.

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<wa-split-panel position="75">
  <div
    slot="start"
    style="
      height: 200px;
      background: var(--wa-color-surface-lowered);
      display: flex;
      align-items: center;
      justify-content: center;
      overflow: hidden;
    "
  >
    Start
  </div>
  <div
    slot="end"
    style="
      height: 200px;
      background: var(--wa-color-surface-lowered);
      display: flex;
      align-items: center;
      justify-content: center;
      overflow: hidden;
    "
  >
    End
  </div>
</wa-split-panel>

Initial Position in Pixels

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To set the initial position in pixels instead of a percentage, use the position-in-pixels attribute.

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<wa-split-panel position-in-pixels="150">
  <div
    slot="start"
    style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    Start
  </div>
  <div
    slot="end"
    style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    End
  </div>
</wa-split-panel>

Orientation

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Set the orientation attribute to vertical and provide a height to render the split panel in a vertical orientation where the start and end panels are stacked.

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<wa-split-panel orientation="vertical" style="height: 400px;">
  <div
    slot="start"
    style="height: 100%; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    Start
  </div>
  <div
    slot="end"
    style="height: 100%; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    End
  </div>
</wa-split-panel>

Snapping

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To snap panels at specific positions while dragging, add the snap attribute with one or more space-separated values. Values must be in pixels or percentages. For example, to snap the panel at 100px and 50%, use snap="100px 50%". You can also customize how close the divider must be before snapping with the snap-threshold attribute.

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<div class="split-panel-snapping">
  <wa-split-panel snap="100px 50%">
    <div
      slot="start"
      style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
    >
      Start
    </div>
    <div
      slot="end"
      style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
    >
      End
    </div>
  </wa-split-panel>

  <div class="split-panel-snapping-dots"></div>
</div>

<style>
  .split-panel-snapping {
    position: relative;
  }

  .split-panel-snapping-dots::before,
  .split-panel-snapping-dots::after {
    content: '';
    position: absolute;
    bottom: -12px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--wa-color-neutral-fill-loud);
    transform: translateX(-3px);
  }

  .split-panel-snapping-dots::before {
    left: 100px;
  }

  .split-panel-snapping-dots::after {
    left: 50%;
  }
</style>

Disabled

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Add the disabled attribute to prevent the divider from being repositioned.

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<wa-split-panel disabled>
  <div
    slot="start"
    style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    Start
  </div>
  <div
    slot="end"
    style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    End
  </div>
</wa-split-panel>

Setting the Primary Panel

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By default, both panels will grow or shrink proportionally when the host element is resized. If a primary panel is designated, it will maintain its size and the secondary panel will grow or shrink to fit the remaining space. You can set the primary panel to start or end using the primary attribute.

Try resizing the example below with each option and notice how the panels respond.

  
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<div class="split-panel-primary">
  <wa-split-panel>
    <div
      slot="start"
      style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
    >
      Start
    </div>
    <div
      slot="end"
      style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
    >
      End
    </div>
  </wa-split-panel>

  <wa-divider></wa-divider>

  <wa-select label="Primary Panel" style="max-width: 200px;">
    <wa-option value="" selected>None</wa-option>
    <wa-option value="start">Start</wa-option>
    <wa-option value="end">End</wa-option>
  </wa-select>
</div>

<script>
  const container = document.querySelector('.split-panel-primary');
  const splitPanel = container.querySelector('wa-split-panel');
  const select = container.querySelector('wa-select');

  select.addEventListener('change', () => (splitPanel.primary = select.value));
</script>

Min & Max

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To set a minimum or maximum size of the primary panel, use the --min and --max custom properties. Since the secondary panel is flexible, size constraints can only be applied to the primary panel. If no primary panel is designated, these constraints will be applied to the start panel.

This examples demonstrates how you can ensure both panels are at least 150px using --min, --max, and the calc() function.

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<wa-split-panel style="--min: 150px; --max: calc(100% - 150px);">
  <div
    slot="start"
    style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    Start
  </div>
  <div
    slot="end"
    style="height: 200px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden;"
  >
    End
  </div>
</wa-split-panel>

Nested Split Panels

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Create complex layouts that can be repositioned independently by nesting split panels.

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<wa-split-panel>
  <div
    slot="start"
    style="height: 400px; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden"
  >
    Start
  </div>
  <div slot="end">
    <wa-split-panel orientation="vertical" style="height: 400px;">
      <div
        slot="start"
        style="height: 100%; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden"
      >
        Top
      </div>
      <div
        slot="end"
        style="height: 100%; background: var(--wa-color-surface-lowered); display: flex; align-items: center; justify-content: center; overflow: hidden"
      >
        Bottom
      </div>
    </wa-split-panel>
  </div>
</wa-split-panel>

Customizing the Divider

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You can target the divider part to apply CSS properties to the divider. To add a custom handle, slot an icon into the divider slot. When customizing the divider, make sure to think about focus styles for keyboard users.

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<wa-split-panel style="--divider-width: 20px;">
  <wa-icon slot="divider" name="grip-vertical" variant="solid"></wa-icon>
  <div
    slot="start"
    style="
      height: 200px;
      background: var(--wa-color-surface-lowered);
      display: flex;
      align-items: center;
      justify-content: center;
      overflow: hidden;
    "
  >
    Start
  </div>
  <div
    slot="end"
    style="
      height: 200px;
      background: var(--wa-color-surface-lowered);
      display: flex;
      align-items: center;
      justify-content: center;
      overflow: hidden;
    "
  >
    End
  </div>
</wa-split-panel>

Here's a more elaborate example that changes the divider's color and width and adds a styled handle.

  
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<div class="split-panel-divider">
  <wa-split-panel>
    <wa-icon slot="divider" name="grip-vertical" variant="solid"></wa-icon>
    <div
      slot="start"
      style="
        height: 200px;
        background: var(--wa-color-surface-lowered);
        display: flex;
        align-items: center;
        justify-content: center;
        overflow: hidden;
      "
    >
      Start
    </div>
    <div
      slot="end"
      style="
        height: 200px;
        background: var(--wa-color-surface-lowered);
        display: flex;
        align-items: center;
        justify-content: center;
        overflow: hidden;
      "
    >
      End
    </div>
  </wa-split-panel>
</div>

<style>
  .split-panel-divider wa-split-panel {
    --divider-width: 4px;
  }

  .split-panel-divider wa-split-panel::part(divider) {
    background-color: var(--wa-color-red-50);
  }

  .split-panel-divider wa-icon {
    position: absolute;
    border-radius: var(--wa-border-radius-l);
    background: var(--wa-color-red-50);
    color: white;
    padding: 0.5rem 0.25rem;
  }

  .split-panel-divider wa-split-panel::part(divider):focus-visible {
    background-color: var(--wa-color-blue-50);
  }

  .split-panel-divider wa-split-panel:focus-within wa-icon {
    background-color: var(--wa-color-blue-50);
    color: white;
  }
</style>

Importing

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If you're using the autoloader or a hosted project, components load on demand — no manual import needed. To cherry-pick a component manually, use one of the following snippets.

CDN

npm

Self-Hosted

React

Import this component directly from the CDN:

import 'https://ka-f.webawesome.com/webawesome@0.17.0/components/split-panel/split-panel.js';

After installing Web Awesome via npm, import this component:

import '@awesome.me/webawesome/dist/components/split-panel/split-panel.js';

If you're self-hosting Web Awesome, import this component from your server:

import './webawesome/dist/components/split-panel/split-panel.js';

To import this component for React 18 or below, use the following code:

import WaSplitPanel from '@awesome.me/webawesome/dist/react/split-panel/index.js';

Slots

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Learn more about using slots.

Name	Description
`divider`	The divider. Useful for slotting in a custom icon that renders as a handle.
`end`	Content to place in the end panel.
`start`	Content to place in the start panel.

Attributes & Properties

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Learn more about attributes and properties.

Name	Description	Reflects
`disabled` `disabled`	Disables resizing. Note that the position may still change as a result of resizing the host element. Type `boolean` Default `false`
`orientation` `orientation`	Sets the split panel's orientation. Type `'horizontal' \| 'vertical'` Default `'horizontal'`
`position` `position`	The current position of the divider from the primary panel's edge as a percentage 0-100. Defaults to 50% of the container's initial size. Type `number` Default `50`
`positionInPixels` `position-in-pixels`	The current position of the divider from the primary panel's edge in pixels. Type `number`
`primary` `primary`	If no primary panel is designated, both panels will resize proportionally when the host element is resized. If a primary panel is designated, it will maintain its size and the other panel will grow or shrink as needed when the host element is resized. Type `'start' \| 'end' \| undefined`
`snap` `snap`	One or more space-separated values at which the divider should snap. Values can be in pixels or percentages, e.g. `"100px 50%"`. Type `string \| undefined`
`snapThreshold` `snap-threshold`	How close the divider must be to a snap point until snapping occurs. Type `number` Default `12`

Events

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Learn more about events.

Name	Description
`wa-reposition`	Emitted when the divider's position changes.

CSS Custom Properties

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Learn more about CSS custom properties.

Name	Description
`--divider-hit-area`	The invisible region around the divider where dragging can occur. This is usually wider than the divider to facilitate easier dragging. Default `12px`
`--divider-width`	The width of the visible divider. Default `4px`
`--max`	The maximum allowed size of the primary panel. Default `100%`
`--min`	The minimum allowed size of the primary panel. Default `0`

CSS Parts

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Learn more about CSS parts.

Name	Description	CSS selector
`divider`	The divider that separates the start and end panels.	`::part(divider)`
`end`	The end panel.	`::part(end)`
`panel`	Targets both the start and end panels.	`::part(panel)`
`start`	The start panel.	`::part(start)`

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Split Panel

Examples

Initial Position

Initial Position in Pixels

Orientation

Snapping

Disabled

Setting the Primary Panel

Min & Max

Nested Split Panels

Customizing the Divider

Importing

Slots

Attributes & Properties

Events

CSS Custom Properties

CSS Parts

Quick Links

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