Checkbox

A native-feeling checkbox built on a role="checkbox" element. It generates a hidden native <input type="checkbox"> for form submission, supports indeterminate state, and emits change events on user interaction.

import { Checkbox } from "@areia/slots";

document.querySelector("#root")!.innerHTML = `
  <label>
    <span
      data-slot="checkbox"
      class="win95-check mr-2 data-[checked]:bg-blue-900"
    >
      <span data-slot="checkbox-indicator" class="win95-check-mark"></span>
    </span>
    Accept terms and conditions
  </label>
`;

const root = document.querySelector('[data-slot="checkbox"]')!;
const controller = Checkbox.createCheckbox(root, {
  defaultChecked: false,
  name: "terms",
});

Import

import { Checkbox } from "@areia/slots";

Usage

import { Checkbox } from "@areia/slots";

// Auto-bind a single root
const root = document.querySelector('[data-slot="checkbox"]');
const checkbox = Checkbox.createCheckbox(root, {
  name: "accept",
  value: "yes",
});

// Listen for state changes
root.addEventListener("checkbox:change", (e) => {
  console.log(e.detail.checked);
});

// Auto-bind all unbound roots in scope
const controllers = Checkbox.create();

Expected Markup

The root element receives role="checkbox" and keyboard handling. A hidden native <input type="checkbox"> is generated and inserted after the root for form participation. The optional checkbox-indicator slot is shown or hidden based on checked/indeterminate state.

<label>
  <span data-slot="checkbox">
    <span data-slot="checkbox-indicator">
      <!-- Icon or custom indicator markup -->
    </span>
  </span>
  Accept terms and conditions
</label>

Wrapping the checkbox in a <label> is recommended — the controller detects wrapping labels and label[for] associations so that clicking the label text toggles the checkbox.

Minimal Markup (no indicator)

<span data-slot="checkbox"></span>

Generated Hidden Input

The controller creates a visually hidden native checkbox and inserts it immediately after the root element:

<input
  type="checkbox"
  tabindex="-1"
  aria-hidden="true"
  data-checkbox-generated="input"
  style="position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0;pointer-events:none"
/>

When uncheckedValue is configured, a second hidden input is generated to submit a value even when the checkbox is unchecked.

Data Slots

Slot	Required	Description
`checkbox`	Yes	Root element. Receives `role="checkbox"` and ARIA attrs.
`checkbox-indicator`	No	Visual indicator shown when checked or indeterminate. Hidden otherwise unless `data-keep-mounted` is set.

Generated Attributes

Attribute	Element(s)	Description
`data-checked`	Root, indicator	Present when checked.
`data-unchecked`	Root, indicator	Present when unchecked and not indeterminate.
`data-indeterminate`	Root, indicator	Present when in mixed state.
`data-disabled`	Root, indicator	Present when disabled.
`data-readonly`	Root, indicator	Present when read-only.
`data-required`	Root, indicator	Present when required.
`role`	Root	Set to `"checkbox"`.
`aria-checked`	Root	`"true"`, `"false"`, or `"mixed"`.
`aria-disabled`	Root	`"true"` or removed.
`aria-readonly`	Root	`"true"` or removed.
`aria-required`	Root	`"true"` or removed.
`aria-labelledby`	Root	Merged from wrapping `<label>` and `[for]` associations.

Events

Outbound

Event	Detail	Description
`checkbox:change`	`{ checked: boolean }`	Fired on the root when the checked state changes via user interaction or the controller.

Inbound

Event	Detail	Description
`checkbox:set`	`boolean` or `{ checked: boolean }` or `{ checked: boolean; indeterminate?: boolean }`	Dispatch on the root to set the checked (and optionally indeterminate) state. Supports flat `boolean` shorthand.

API Reference

Options

Option	Type	Default	Description
`defaultChecked`	`boolean`	`false`	Initial checked state.
`indeterminate`	`boolean`	`false`	Initial mixed state. Cleared when the user toggles the checkbox.
`disabled`	`boolean`	`false`	Disable user interaction and exclude from form submission.
`readOnly`	`boolean`	`false`	Prevent user interaction while keeping the value submittable.
`required`	`boolean`	`false`	Require a checked value for native form validation.
`name`	`string`	—	Form field name.
`form`	`string`	—	Form owner ID for generated inputs.
`value`	`string`	—	Submitted value when checked. Defaults to the native checkbox `"on"`.
`uncheckedValue`	`string`	—	Submitted value when unchecked. Creates an additional hidden input.
`onCheckedChange`	`(checked: boolean) => void`	—	Called when the checked state changes.

Controller

Member	Type	Description
`checked`	`boolean` (getter)	Current checked state.
`indeterminate`	`boolean` (getter)	Current indeterminate state.
`toggle()`	`() => void`	Toggle the checked state and clear indeterminate.
`check()`	`() => void`	Set checked to `true` and clear indeterminate.
`uncheck()`	`() => void`	Set checked to `false` and clear indeterminate.
`setChecked(checked, ind?)`	`(checked: boolean, indeterminate?: boolean) => void`	Set checked and optionally indeterminate state.
`setIndeterminate(ind)`	`(indeterminate: boolean) => void`	Set indeterminate without changing checked.
`destroy()`	`() => void`	Remove listeners and generated inputs.

Controller

The controller is returned by Checkbox.createCheckbox() and provides imperative control over the checkbox state.

const checkbox = Checkbox.createCheckbox(root, {
  name: "terms",
});

// Toggle
checkbox.toggle();

// Force check
checkbox.check();

// Force uncheck
checkbox.uncheck();

// Set checked and indeterminate together
checkbox.setChecked(true, true); // indeterminate

// Set only indeterminate
checkbox.setIndeterminate(true);

// Read state
console.log(checkbox.checked); // true
console.log(checkbox.indeterminate); // true

// Clean up
checkbox.destroy();

Form Integration

The generated hidden input participates in standard form submission and FormData. When uncheckedValue is set, an extra hidden input ensures a value is submitted even when the checkbox is unchecked. The controller also listens for the form's reset event and synchronizes state accordingly.

<form>
  <span
    data-slot="checkbox"
    data-name="accept"
    data-value="yes"
    data-unchecked-value="no"
  >
    <span data-slot="checkbox-indicator"></span>
  </span>
  Accept terms
</form>