/**
* @file ds-checkbox.js
* @summary A custom Web Component that wraps a native checkbox input element.
* @description
* The `ds-checkbox` component provides a styled and functional checkbox.
* It supports both single checkboxes and groups of checkboxes for multiple selections.
*
* @element ds-checkbox
* @extends BaseComponent
*
* @attr {string} name - The name of the checkbox, used when submitting form data.
* @attr {string} value - The value of the checkbox when checked.
* @attr {boolean} checked - If present, the checkbox is selected.
* @attr {boolean} disabled - If present, the checkbox cannot be interacted with.
* @attr {boolean} readonly - If present, the checkbox cannot be modified by the user.
* @attr {boolean} required - If present, the checkbox must be checked before form submission.
* @attr {string} id - A unique identifier for the checkbox, useful for associating with labels.
*
* @property {boolean} checked - Gets or sets the checked state of the checkbox.
* @property {string} value - Gets or sets the value of the checkbox.
* @property {string} name - Gets or sets the name of the checkbox.
* @property {boolean} disabled - Gets or sets the disabled state of the checkbox.
* @property {boolean} readonly - Gets or sets the readonly state of the checkbox.
* @property {boolean} required - Gets or sets the required state of the checkbox.
*
* @fires input - re-emitted from host (bubbles, composed)
* @fires change - re-emitted from host (bubbles, composed)
* @fires focus - re-emitted from host (bubbles, composed)
* @fires blur - re-emitted from host (bubbles, composed)
* @fires ds-change - custom event with { detail: { value } }
*
* @example
* <!-- Basic checkbox -->
* <ds-checkbox name="agree" value="yes" id="agree-terms">I agree to the terms</ds-checkbox>
*
* @example
* <!-- Checkbox with default selection -->
* <ds-checkbox name="newsletter" value="subscribe" checked>Subscribe to newsletter</ds-checkbox>
*
* @example
* <!-- Multiple checkboxes for preferences -->
* <ds-checkbox name="preferences" value="email">Email notifications</ds-checkbox>
* <ds-checkbox name="preferences" value="sms">SMS notifications</ds-checkbox>
* <ds-checkbox name="preferences" value="push">Push notifications</ds-checkbox>
*/
import BaseComponent from './base-component.js';
import { emit } from '../utils/emit.js';
class DsCheckbox extends BaseComponent {
constructor() {
// ARIA config for ds-checkbox
const ariaConfig = {
staticAriaAttributes: { role: 'checkbox' },
dynamicAriaAttributes: [
'aria-label',
'aria-describedby',
'aria-required',
'aria-invalid',
'aria-checked'
],
requiredAriaAttributes: [], // none required, but warn about missing labels
referenceAttributes: ['aria-describedby'],
tokenValidation: {
'aria-checked': ['true', 'false', 'mixed', 'undefined'],
'aria-invalid': ['true', 'false', 'grammar', 'spelling']
}
};
const template = document.createElement('template');
template.innerHTML = `
<style>
@import url('/src/styles/styles.css');
:host {
display: inline-block;
}
.wrapper {
display: flex;
align-items: center;
}
</style>
<div class="wrapper">
<input type="checkbox" id="checkbox" part="checkbox">
<slot></slot>
</div>
`;
super({
template: template.innerHTML,
targetSelector: 'input[type="checkbox"]',
ariaConfig,
observedAttributes: ['name', 'value', 'checked', 'disabled', 'readonly', 'required', 'id']
});
this.checkbox = this.shadowRoot.querySelector('input[type="checkbox"]');
this._onInput = this._onInput.bind(this);
this._onChange = this._onChange.bind(this);
this._onFocus = this._onFocus.bind(this);
this._onBlur = this._onBlur.bind(this);
}
/**
* Defines which attributes the component observes for changes.
* @returns {Array<string>} An array of attribute names to observe.
*/
static get observedAttributes() {
return ['name', 'value', 'checked', 'disabled', 'readonly', 'required', 'id', 'aria-label', 'aria-describedby', 'aria-required', 'aria-invalid', 'aria-checked'];
}
/**
* Called when one of the component's observed attributes is added, removed, or changed.
* @param {string} name - The name of the attribute that changed.
* @param {string|null} oldValue - The attribute's old value.
* @param {string|null} newValue - The attribute's new value.
*/
attributeChangedCallback(name, oldValue, newValue) {
// Call parent method first
super.attributeChangedCallback(name, oldValue, newValue);
if (oldValue === newValue) return; // No change
switch (name) {
case 'name':
this.checkbox.name = newValue || '';
break;
case 'value':
this.checkbox.value = newValue || '';
break;
case 'checked':
if (this.hasAttribute('checked')) {
this.checkbox.checked = true;
} else {
this.checkbox.checked = false;
}
break;
case 'disabled':
if (this.hasAttribute('disabled')) {
this.checkbox.disabled = true;
} else {
this.checkbox.disabled = false;
}
break;
case 'readonly':
if (this.hasAttribute('readonly')) {
this.checkbox.readOnly = true;
} else {
this.checkbox.readOnly = false;
}
break;
case 'required':
if (this.hasAttribute('required')) {
this.checkbox.required = true;
} else {
this.checkbox.required = false;
}
break;
case 'id':
this.checkbox.id = newValue || '';
break;
}
}
/**
* Gets the checked state of the checkbox.
* @returns {boolean} Whether the checkbox is checked.
*/
get checked() {
return this.checkbox.checked;
}
/**
* Sets the checked state of the checkbox.
* @param {boolean} val - Whether to check the checkbox.
*/
set checked(val) {
this.checkbox.checked = val;
}
/**
* Gets the value of the checkbox.
* @returns {string} The checkbox's value.
*/
get value() {
return this.checkbox.value;
}
/**
* Sets the value of the checkbox.
* @param {string} val - The new value to set.
*/
set value(val) {
const v = val ?? '';
if (this.checkbox.value !== v) {
this.checkbox.value = v;
}
this.setAttribute('value', v);
}
/**
* Gets the name of the checkbox.
* @returns {string} The checkbox's name.
*/
get name() {
return this.checkbox.name;
}
/**
* Sets the name of the checkbox.
* @param {string} val - The new name to set.
*/
set name(val) {
this.checkbox.name = val;
}
/**
* Gets the disabled state of the checkbox.
* @returns {boolean} Whether the checkbox is disabled.
*/
get disabled() {
return this.checkbox.disabled;
}
/**
* Sets the disabled state of the checkbox.
* @param {boolean} val - Whether to disable the checkbox.
*/
set disabled(val) {
this.checkbox.disabled = val;
}
/**
* Gets the readonly state of the checkbox.
* @returns {boolean} Whether the checkbox is readonly.
*/
get readonly() {
return this.checkbox.readOnly;
}
/**
* Sets the readonly state of the checkbox.
* @param {boolean} val - Whether to make the checkbox readonly.
*/
set readonly(val) {
this.checkbox.readOnly = val;
}
/**
* Gets the required state of the checkbox.
* @returns {boolean} Whether the checkbox is required.
*/
get required() {
return this.checkbox.required;
}
/**
* Sets the required state of the checkbox.
* @param {boolean} val - Whether to make the checkbox required.
*/
set required(val) {
this.checkbox.required = val;
}
connectedCallback() {
if (super.connectedCallback) super.connectedCallback();
this.checkbox.addEventListener('input', this._onInput);
this.checkbox.addEventListener('change', this._onChange);
this.checkbox.addEventListener('focus', this._onFocus);
this.checkbox.addEventListener('blur', this._onBlur);
}
disconnectedCallback() {
if (super.disconnectedCallback) super.disconnectedCallback();
this.checkbox.removeEventListener('input', this._onInput);
this.checkbox.removeEventListener('change', this._onChange);
this.checkbox.removeEventListener('focus', this._onFocus);
this.checkbox.removeEventListener('blur', this._onBlur);
}
_onInput() {
this.dispatchEvent(new Event('input', { bubbles: true, composed: true }));
emit(this, 'ds-change', { value: this.checkbox.checked });
}
_onChange() {
this.dispatchEvent(new Event('change', { bubbles: true, composed: true }));
}
_onFocus() {
this.dispatchEvent(new Event('focus', { bubbles: true, composed: true }));
}
_onBlur() {
this.dispatchEvent(new Event('blur', { bubbles: true, composed: true }));
}
// ARIA property accessors
get ariaLabel() {
const value = this.checkbox.getAttribute('aria-label');
return value === null ? null : value;
}
set ariaLabel(val) {
if (val === null || val === undefined) {
this.checkbox.removeAttribute('aria-label');
} else {
this.checkbox.setAttribute('aria-label', val);
}
}
get ariaDescribedBy() {
const value = this.checkbox.getAttribute('aria-describedby');
return value === null ? null : value;
}
set ariaDescribedBy(val) {
if (val === null || val === undefined) {
this.checkbox.removeAttribute('aria-describedby');
} else {
this.checkbox.setAttribute('aria-describedby', val);
}
}
get ariaRequired() {
const value = this.checkbox.getAttribute('aria-required');
return value === null ? null : value;
}
set ariaRequired(val) {
if (val === null || val === undefined) {
this.checkbox.removeAttribute('aria-required');
} else {
this.checkbox.setAttribute('aria-required', val);
}
}
get ariaInvalid() {
const value = this.checkbox.getAttribute('aria-invalid');
return value === null ? null : value;
}
set ariaInvalid(val) {
if (val === null || val === undefined) {
this.checkbox.removeAttribute('aria-invalid');
} else {
this.checkbox.setAttribute('aria-invalid', val);
}
}
get ariaChecked() {
const value = this.checkbox.getAttribute('aria-checked');
return value === null ? null : value;
}
set ariaChecked(val) {
if (val === null || val === undefined) {
this.checkbox.removeAttribute('aria-checked');
} else {
this.checkbox.setAttribute('aria-checked', val);
}
}
// Override validateARIA for checkbox-specific checks
validateARIA() {
const errors = super.validateARIA ? super.validateARIA() : [];
// Accessible name check - check host element's text content and ARIA attributes
const hostTextContent = this.textContent.trim();
const hostAriaLabel = this.getAttribute('aria-label');
const hostAriaLabelledBy = this.getAttribute('aria-labelledby');
const checkboxAriaLabel = this.checkbox.getAttribute('aria-label');
const checkboxAriaLabelledBy = this.checkbox.getAttribute('aria-labelledby');
const hasName = hostTextContent || hostAriaLabel || hostAriaLabelledBy || checkboxAriaLabel || checkboxAriaLabelledBy;
if (!hasName) {
errors.push('Checkbox has no accessible name (text, aria-label, or aria-labelledby required)');
}
// aria-checked state management
if (this.checkbox.hasAttribute('aria-checked')) {
const val = this.checkbox.getAttribute('aria-checked');
if (!['true', 'false', 'mixed', 'undefined'].includes(val)) {
errors.push(`Invalid aria-checked value: ${val}`);
}
}
// aria-describedby references
if (this.checkbox.hasAttribute('aria-describedby')) {
const refError = this.checkAriaReferences('aria-describedby', this.checkbox.getAttribute('aria-describedby'));
if (refError) errors.push(refError);
}
return errors;
}
}
// Register the custom element
if (!customElements.get('ds-checkbox')) {
customElements.define('ds-checkbox', DsCheckbox);
}
// Export for use in other modules
export default DsCheckbox;