feat(radio-group): add helperText and errorText properties

core/src/components.d.ts

@@ -2307,6 +2307,14 @@ export namespace Components {
           * This property allows developers to specify a custom function or property name for comparing objects when determining the selected option in the ion-radio-group. When not specified, the default behavior will use strict equality (===) for comparison.
          */
         "compareWith"?: string | RadioGroupCompareFn | null;
+        /**
+          * The error text to display at the top of the radio group.
+         */
+        "errorText"?: string;
+        /**
+          * The helper text to display at the top of the radio group.
+         */
+        "helperText"?: string;
         /**
           * The name of the control, which is submitted with the form data.
          */
@@ -7079,6 +7087,14 @@ declare namespace LocalJSX {
           * This property allows developers to specify a custom function or property name for comparing objects when determining the selected option in the ion-radio-group. When not specified, the default behavior will use strict equality (===) for comparison.
          */
         "compareWith"?: string | RadioGroupCompareFn | null;
+        /**
+          * The error text to display at the top of the radio group.
+         */
+        "errorText"?: string;
+        /**
+          * The helper text to display at the top of the radio group.
+         */
+        "helperText"?: string;
         /**
           * The name of the control, which is submitted with the form data.
          */

core/src/components/radio-group/radio-group.ios.scss

@@ -0,0 +1,12 @@
+@import "../../themes/ionic.globals.ios";
+@import "./radio-group";
+@import "../item/item.ios.vars";
+
+// iOS Radio Group in List
+// --------------------------------------------------
+
+// Add padding to the error and helper text when used in a
+// list to align them with the list header and item text.
+ion-list .supporting-text {
+  @include padding-horizontal($item-ios-padding-start, $item-ios-padding-end);
+}

core/src/components/radio-group/radio-group.md.scss

@@ -0,0 +1,12 @@
+@import "../../themes/ionic.globals.md";
+@import "./radio-group";
+@import "../item/item.md.vars";
+
+// Material Design Radio Group in List
+// --------------------------------------------------
+
+// Add padding to the error and helper text when used in a
+// list to align them with the list header and item text.
+ion-list .supporting-text {
+  @include padding-horizontal($item-md-padding-start, $item-md-padding-end);
+}

core/src/components/radio-group/radio-group.scss

@@ -0,0 +1,40 @@
+@import "../../themes/ionic.globals";
+
+// Radio Group
+// --------------------------------------------------
+
+ion-radio-group {
+  display: block;
+}
+
+// Radio Group: Supporting Text
+// --------------------------------------------------
+
+.supporting-text {
+  line-height: 1.5;
+}
+
+/**
+ * Error text should only be shown when .ion-invalid is
+ * present on the radio group. Otherwise the helper text should
+ * be shown.
+ */
+.error-text {
+  display: none;
+
+  color: var(--ion-color-danger, #eb445a);
+}
+
+.helper-text {
+  display: block;
+
+  color: var(--ion-color-step-550, #737373);
+}
+
+.ion-touched.ion-invalid .error-text {
+  display: block;
+}
+
+.ion-touched.ion-invalid .helper-text {
+  display: none;
+}

core/src/components/radio-group/radio-group.tsx

@@ -8,9 +8,15 @@ import type { RadioGroupChangeEventDetail, RadioGroupCompareFn } from './radio-g
 
 @Component({
   tag: 'ion-radio-group',
+  styleUrls: {
+    ios: 'radio-group.ios.scss',
+    md: 'radio-group.md.scss',
+  },
 })
 export class RadioGroup implements ComponentInterface {
   private inputId = `ion-rg-${radioGroupIds++}`;
+  private helperTextId = `${this.inputId}-helper-text`;
+  private errorTextId = `${this.inputId}-error-text`;
   private labelId = `${this.inputId}-lbl`;
   private label?: HTMLIonLabelElement | null;
 
@@ -39,6 +45,16 @@ export class RadioGroup implements ComponentInterface {
    */
   @Prop({ mutable: true }) value?: any | null;
 
+  /**
+   * The helper text to display at the top of the radio group.
+   */
+  @Prop() helperText?: string;
+
+  /**
+   * The error text to display at the top of the radio group.
+   */
+  @Prop() errorText?: string;
+
   @Watch('value')
   valueChanged(value: any | undefined) {
     this.setRadioTabindex(value);
@@ -224,13 +240,62 @@ export class RadioGroup implements ComponentInterface {
     radioToFocus?.setFocus();
   }
 
+  /**
+   * Renders the helper text or error text values
+   */
+  private renderHintText() {
+    const { helperText, errorText, helperTextId, errorTextId } = this;
+
+    const hasHintText = !!helperText || !!errorText;
+    if (!hasHintText) {
+      return;
+    }
+
+    return (
+      <div class="supporting-text">
+        <div id={helperTextId} class="helper-text">
+          {helperText}
+        </div>
+        <div id={errorTextId} class="error-text">
+          {errorText}
+        </div>
+      </div>
+    );
+  }
+
+  private getHintTextID(): string | undefined {
+    const { el, helperText, errorText, helperTextId, errorTextId } = this;
+
+    if (el.classList.contains('ion-touched') && el.classList.contains('ion-invalid') && errorText) {
+      return errorTextId;
+    }
+
+    if (helperText) {
+      return helperTextId;
+    }
+
+    return undefined;
+  }
+
   render() {
     const { label, labelId, el, name, value } = this;
     const mode = getIonMode(this);
 
     renderHiddenInput(true, el, name, value, false);
 
-    return <Host role="radiogroup" aria-labelledby={label ? labelId : null} onClick={this.onClick} class={mode}></Host>;
+    return (
+      <Host
+        role="radiogroup"
+        aria-labelledby={label ? labelId : null}
+        aria-describedby={this.getHintTextID()}
+        aria-invalid={this.getHintTextID() === this.errorTextId}
+        onClick={this.onClick}
+        class={mode}
+      >
+        {this.renderHintText()}
+        <slot></slot>
+      </Host>
+    );
   }
 }
 

packages/angular/src/directives/proxies.ts

@@ -1639,14 +1639,14 @@ export declare interface IonRadio extends Components.IonRadio {
 
 
 @ProxyCmp({
-  inputs: ['allowEmptySelection', 'compareWith', 'name', 'value']
+  inputs: ['allowEmptySelection', 'compareWith', 'errorText', 'helperText', 'name', 'value']
 })
 @Component({
   selector: 'ion-radio-group',
   changeDetection: ChangeDetectionStrategy.OnPush,
   template: '<ng-content></ng-content>',
   // eslint-disable-next-line @angular-eslint/no-inputs-metadata-property
-  inputs: ['allowEmptySelection', 'compareWith', 'name', 'value'],
+  inputs: ['allowEmptySelection', 'compareWith', 'errorText', 'helperText', 'name', 'value'],
 })
 export class IonRadioGroup {
   protected el: HTMLIonRadioGroupElement;

packages/vue/src/proxies.ts

@@ -696,6 +696,8 @@ export const IonRadioGroup = /*@__PURE__*/ defineContainer<JSX.IonRadioGroup, JS
   'compareWith',
   'name',
   'value',
+  'helperText',
+  'errorText',
   'ionChange',
   'ionValueChange'
 ], [