@window-splitter/state

@window-splitter/state

A state machine for a WAI-ARIA compliant window splitter. This package can be used to build your own window splitter for a framework or even vanilla html/js.

If you're using a framework like React, you should use the framework package instead.

Read the full docs

Install

npm install @window-splitter/state
yarn add @window-splitter/state
pnpm add @window-splitter/state

Usage

This is an example of how to use the machine to create a window splitter. This is very simplified and only shows the basics of how to use the state machine. Actually integrating with a framework would look a lot different.

In a vanilla html/js application you would have something like this:

<div id="group">
  <div id="panel-1">Panel-1</div>
  <div id="resizer-1"></div>
  <div id="panel-2">Panel-2</div>
</div>

And then you would have some javascript to setup the state machine and send events to it.

import {
  groupMachine,
  initializePanel,
  initializePanelHandleData,
} from "@window-splitter/state";

// Setup the state machine
const actor = groupMachine({ groupId: "group" });

// Register the panels with the state machine
actor.send({
  type: "registerPanel",
  data: initializePanel({ id: "panel-1" }),
});
actor.send({
  type: "registerPanelHandle",
  data: initializePanelHandleData({ id: "resizer-1", size: "10px" }),
});
actor.send({
  type: "registerPanel",
  data: initializePanel({ id: "panel-2" }),
});

// Set the size of the group, typically measured in the browser after the initial render
actor.send({ type: "setSize", size: { width: 500, height: 200 } });
// The state machine relies on css grid to calculate the initial sizes of the panels
// This next action would be sent after measuring the initial sizes rendered by the browser
actor.send({
  type: "setActualItemsSize",
  childrenSizes: {
    "panel-1": { width: 245, height: 200 },
    "panel-2": { width: 245, height: 200 },
  },
});

// Send some events to drag a handle
actor.send({ type: "dragHandleStart", handleId: "resizer-1" });
actor.send({
  type: "dragHandle",
  handleId: "resizer-1",
  value: dragHandlePayload({ delta: 10 }),
});
actor.send({ type: "dragHandleEnd", handleId: "resizer-1" });

API

groupMachine

The state machine is exported as groupMachine and can be used to create a window splitter.

groupMachine.input

The context of the state machine is an object with the following shape:

• orientation: The orientation of the group. This can be either "horizontal" or "vertical"
• groupId: The id of the group
• initialItems: An array of items to initialize the group with.

Events

For a full list of events and their payloads see the source code.

• registerPanel: Register a new panel with the state machine
• registerDynamicPanel: Register a new panel after the initial render
• unregisterPanel: Unregister a panel from the state machine
• registerPanelHandle: Register a new panel handle with the state machine
• unregisterPanelHandle: Unregister a panel handle from the state machine
• setSize: Set the size of the group after the initial render
• setActualItemsSize: Set the size of the group items after the initial render
• setOrientation: Set the orientation of the group
• dragHandleStart: Start a drag interaction
• dragHandle: Update the layout according to how the handle moved
• dragHandleEnd: End a drag interaction
• collapsePanel: Collapse a panel
• expandPanel: Expand a panel
• setPanelPixelSize: Set the size of a panel in pixels

Utilities

• buildTemplate - Build the grid template from the item values.
• getCollapsiblePanelForHandleId - Get the handle closest to the target panel.
• getGroupSize - Get the size of the group in pixels.
• getPanelWithId - Get a panel with a particular ID.
• getUnitPercentageValue - Converts a Unit to a percentage of the group size.
• getUnitPixelValue - Converts a Unit to a pixel value.
• initializePanel - Initialize a panel for registration with the state machine.
• InitializePanelHandleData - Initialize a panel handle for registration with the state machine.
• isPanelData - Check if the provided item is a panel data object.
• isPanelHandle - Check if the provided item is a panel handle object.
• parseUnit - Parse a Unit from a string.
• prepareSnapshot - For usage with restoring a saved layout state

Changelog

v0.8.3 (Tue Apr 29 2025)

⚠️ Pushed to main

• @window-splitter/interface, @window-splitter/react, @window-splitter/solid, @window-splitter/state
  • fix repo links (@hipstersmoothie)

Authors: 1

• Andrew Lisowski (@hipstersmoothie)