Add checkbox help text

docs/pages/components/checkbox.md

@@ -89,6 +89,20 @@ const App = () => (
 );
 ```
 
+### Help Text
+
+Add descriptive help text to a switch with the `help-text` attribute. For help texts that contain HTML, use the `help-text` slot instead.
+
+```html:preview
+<sl-checkbox help-text="What should the user know about the checkbox?">Label</sl-checkbox>
+```
+
+```jsx:react
+import SlCheckbox from '@shoelace-style/shoelace/dist/react/checkbox';
+
+const App = () => <SlCheckbox help-text="What should the user know about the switch?">Label</SlCheckbox>;
+```
+
 ### Custom Validity
 
 Use the `setCustomValidity()` method to set a custom validation message. This will prevent the form from submitting and make the browser display the error message you provide. To clear the error, call this function with an empty string.

docs/pages/components/switch.md

@@ -84,6 +84,8 @@ Add descriptive help text to a switch with the `help-text` attribute. For help t
 ```
 
 ```jsx:react
+import SlSwitch from '@shoelace-style/shoelace/dist/react/checkbox';
+
 const App = () => <SlSwitch help-text="What should the user know about the switch?">Label</SlSwitch>;
 ```
 

docs/pages/resources/changelog.md

@@ -18,6 +18,8 @@ New versions of Shoelace are released as-needed and generally occur when a criti
 
 ## 2.13.1
 
+- Added help text to `<sl-checkbox>`
+- Added help text to `<sl-switch>` [#1800]
 - Fixed a bug where the safe triangle was always visible when selecting nested `<sl-menu>` elements [#1835]
 
 ## 2.13.0

src/components/checkbox/checkbox.component.ts

@@ -1,6 +1,7 @@
 import { classMap } from 'lit/directives/class-map.js';
 import { defaultValue } from '../../internal/default-value.js';
 import { FormControlController } from '../../internal/form.js';
+import { HasSlotController } from '../../internal/slot.js';
 import { html } from 'lit';
 import { ifDefined } from 'lit/directives/if-defined.js';
 import { live } from 'lit/directives/live.js';
@@ -21,6 +22,7 @@ import type { ShoelaceFormControl } from '../../internal/shoelace-element.js';
  * @dependency sl-icon
  *
  * @slot - The checkbox's label.
+ * @slot help-text - Text that describes how to use the checkbox. Alternatively, you can use the `help-text` attribute.
  *
  * @event sl-blur - Emitted when the checkbox loses focus.
  * @event sl-change - Emitted when the checked state changes.
@@ -35,6 +37,7 @@ import type { ShoelaceFormControl } from '../../internal/shoelace-element.js';
  * @csspart checked-icon - The checked icon, an `<sl-icon>` element.
  * @csspart indeterminate-icon - The indeterminate icon, an `<sl-icon>` element.
  * @csspart label - The container that wraps the checkbox's label.
+ * @csspart form-control-help-text - The help text's wrapper.
  */
 export default class SlCheckbox extends ShoelaceElement implements ShoelaceFormControl {
   static styles: CSSResultGroup = styles;
@@ -45,6 +48,7 @@ export default class SlCheckbox extends ShoelaceElement implements ShoelaceFormC
     defaultValue: (control: SlCheckbox) => control.defaultChecked,
     setValue: (control: SlCheckbox, checked: boolean) => (control.checked = checked)
   });
+  private readonly hasSlotController = new HasSlotController(this, 'help-text');
 
   @query('input[type="checkbox"]') input: HTMLInputElement;
 
@@ -86,6 +90,9 @@ export default class SlCheckbox extends ShoelaceElement implements ShoelaceFormC
   /** Makes the checkbox a required field. */
   @property({ type: Boolean, reflect: true }) required = false;
 
+  /** The checkbox's help text. If you need to display HTML, use the `help-text` slot instead. */
+  @property({ attribute: 'help-text' }) helpText = '';
+
   /** Gets the validity state object */
   get validity() {
     return this.input.validity;
@@ -178,68 +185,92 @@ export default class SlCheckbox extends ShoelaceElement implements ShoelaceFormC
   }
 
   render() {
+    const hasHelpTextSlot = this.hasSlotController.test('help-text');
+    const hasHelpText = this.helpText ? true : !!hasHelpTextSlot;
+
     //
     // NOTE: we use a <div> around the label slot because of this Chrome bug.
     //
     // https://bugs.chromium.org/p/chromium/issues/detail?id=1413733
     //
     return html`
-      <label
-        part="base"
+      <div
         class=${classMap({
-          checkbox: true,
-          'checkbox--checked': this.checked,
-          'checkbox--disabled': this.disabled,
-          'checkbox--focused': this.hasFocus,
-          'checkbox--indeterminate': this.indeterminate,
-          'checkbox--small': this.size === 'small',
-          'checkbox--medium': this.size === 'medium',
-          'checkbox--large': this.size === 'large'
+          'form-control': true,
+          'form-control--small': this.size === 'small',
+          'form-control--medium': this.size === 'medium',
+          'form-control--large': this.size === 'large',
+          'form-control--has-help-text': hasHelpText
         })}
       >
-        <input
-          class="checkbox__input"
-          type="checkbox"
-          title=${this.title /* An empty title prevents browser validation tooltips from appearing on hover */}
-          name=${this.name}
-          value=${ifDefined(this.value)}
-          .indeterminate=${live(this.indeterminate)}
-          .checked=${live(this.checked)}
-          .disabled=${this.disabled}
-          .required=${this.required}
-          aria-checked=${this.checked ? 'true' : 'false'}
-          @click=${this.handleClick}
-          @input=${this.handleInput}
-          @invalid=${this.handleInvalid}
-          @blur=${this.handleBlur}
-          @focus=${this.handleFocus}
-        />
-
-        <span
-          part="control${this.checked ? ' control--checked' : ''}${this.indeterminate ? ' control--indeterminate' : ''}"
-          class="checkbox__control"
+        <label
+          part="base"
+          class=${classMap({
+            checkbox: true,
+            'checkbox--checked': this.checked,
+            'checkbox--disabled': this.disabled,
+            'checkbox--focused': this.hasFocus,
+            'checkbox--indeterminate': this.indeterminate,
+            'checkbox--small': this.size === 'small',
+            'checkbox--medium': this.size === 'medium',
+            'checkbox--large': this.size === 'large'
+          })}
+        >
+          <input
+            class="checkbox__input"
+            type="checkbox"
+            title=${this.title /* An empty title prevents browser validation tooltips from appearing on hover */}
+            name=${this.name}
+            value=${ifDefined(this.value)}
+            .indeterminate=${live(this.indeterminate)}
+            .checked=${live(this.checked)}
+            .disabled=${this.disabled}
+            .required=${this.required}
+            aria-checked=${this.checked ? 'true' : 'false'}
+            @click=${this.handleClick}
+            @input=${this.handleInput}
+            @invalid=${this.handleInvalid}
+            @blur=${this.handleBlur}
+            @focus=${this.handleFocus}
+          />
+
+          <span
+            part="control${this.checked ? ' control--checked' : ''}${this.indeterminate
+              ? ' control--indeterminate'
+              : ''}"
+            class="checkbox__control"
+          >
+            ${this.checked
+              ? html`
+                  <sl-icon part="checked-icon" class="checkbox__checked-icon" library="system" name="check"></sl-icon>
+                `
+              : ''}
+            ${!this.checked && this.indeterminate
+              ? html`
+                  <sl-icon
+                    part="indeterminate-icon"
+                    class="checkbox__indeterminate-icon"
+                    library="system"
+                    name="indeterminate"
+                  ></sl-icon>
+                `
+              : ''}
+          </span>
+
+          <div part="label" class="checkbox__label">
+            <slot></slot>
+          </div>
+        </label>
+
+        <div
+          aria-hidden=${hasHelpText ? 'false' : 'true'}
+          class="form-control__help-text"
+          id="help-text"
+          part="form-control-help-text"
         >
-          ${this.checked
-            ? html`
-                <sl-icon part="checked-icon" class="checkbox__checked-icon" library="system" name="check"></sl-icon>
-              `
-            : ''}
-          ${!this.checked && this.indeterminate
-            ? html`
-                <sl-icon
-                  part="indeterminate-icon"
-                  class="checkbox__indeterminate-icon"
-                  library="system"
-                  name="indeterminate"
-                ></sl-icon>
-              `
-            : ''}
-        </span>
-
-        <div part="label" class="checkbox__label">
-          <slot></slot>
+          <slot name="help-text">${this.helpText}</slot>
         </div>
-      </label>
+      </div>
     `;
   }
 }

src/components/checkbox/checkbox.styles.ts

@@ -1,8 +1,10 @@
 import { css } from 'lit';
 import componentStyles from '../../styles/component.styles.js';
+import formControlStyles from '../../styles/form-control.styles.js';
 
 export default css`
   ${componentStyles}
+  ${formControlStyles}
 
   :host {
     display: inline-block;

src/components/checkbox/checkbox.test.ts

@@ -23,6 +23,7 @@ describe('<sl-checkbox>', () => {
     expect(el.checked).to.be.false;
     expect(el.indeterminate).to.be.false;
     expect(el.defaultChecked).to.be.false;
+    expect(el.helpText).to.equal('');
   });
 
   it('should have title if title attribute is set', async () => {