fix(select): improve screen reader announcement timing for validation errors

Author: thetaPC

core/src/components/select/select.tsx

@@ -1,5 +1,5 @@
 import type { ComponentInterface, EventEmitter } from '@stencil/core';
-import { Component, Element, Event, Host, Method, Prop, State, Watch, h, forceUpdate } from '@stencil/core';
+import { Build, Component, Element, Event, Host, Method, Prop, State, Watch, h, forceUpdate } from '@stencil/core';
 import type { NotchController } from '@utils/forms';
 import { compareOptions, createNotchController, isOptionSelected } from '@utils/forms';
 import { focusVisibleElement, renderHiddenInput, inheritAttributes } from '@utils/helpers';
@@ -64,6 +64,7 @@ export class Select implements ComponentInterface {
   private inheritedAttributes: Attributes = {};
   private nativeWrapperEl: HTMLElement | undefined;
   private notchSpacerEl: HTMLElement | undefined;
+  private validationObserver?: MutationObserver;
 
   private notchController?: NotchController;
 
@@ -81,6 +82,13 @@ export class Select implements ComponentInterface {
    */
   @State() hasFocus = false;
 
+  /**
+   * Track validation state for proper aria-live announcements.
+   */
+  @State() isInvalid = false;
+
+  @State() private hintTextID?: string;
+
   /**
    * The text to display on the cancel button.
    */
@@ -298,10 +306,49 @@ export class Select implements ComponentInterface {
        */
       forceUpdate(this);
     });
+
+    // Watch for class changes to update validation state.
+    if (Build.isBrowser && typeof MutationObserver !== 'undefined') {
+      this.validationObserver = new MutationObserver(() => {
+        const newIsInvalid = this.checkInvalidState();
+        if (this.isInvalid !== newIsInvalid) {
+          this.isInvalid = newIsInvalid;
+          /**
+           * Screen readers tend to announce changes
+           * to `aria-describedby` when the attribute
+           * is changed during a blur event for a
+           * native form control.
+           * However, the announcement can be spotty
+           * when using a non-native form control
+           * and `forceUpdate()`.
+           * This is due to `forceUpdate()` not being
+           * high priority enough to guarantee
+           * the DOM is updated before the screen reader
+           * announces the attribute change.
+           * By using a promise, it makes sure to
+           * announce the change before the next frame
+           * since promises are high priority.
+           */
+          Promise.resolve().then(() => {
+            this.hintTextID = this.getHintTextID();
+          });
+        }
+      });
+
+      this.validationObserver.observe(el, {
+        attributes: true,
+        attributeFilter: ['class'],
+      });
+    }
+
+    // Always set initial state
+    this.isInvalid = this.checkInvalidState();
   }
 
   componentWillLoad() {
     this.inheritedAttributes = inheritAttributes(this.el, ['aria-label']);
+
+    this.hintTextID = this.getHintTextID();
   }
 
   componentDidLoad() {
@@ -328,6 +375,12 @@ export class Select implements ComponentInterface {
       this.notchController.destroy();
       this.notchController = undefined;
     }
+
+    // Clean up validation observer to prevent memory leaks.
+    if (this.validationObserver) {
+      this.validationObserver.disconnect();
+      this.validationObserver = undefined;
+    }
   }
 
   /**
@@ -1056,8 +1109,8 @@ export class Select implements ComponentInterface {
         aria-label={this.ariaLabel}
         aria-haspopup="dialog"
         aria-expanded={`${isExpanded}`}
-        aria-describedby={this.getHintTextID()}
-        aria-invalid={this.getHintTextID() === this.errorTextId}
+        aria-describedby={this.hintTextID}
+        aria-invalid={this.isInvalid ? 'true' : undefined}
         aria-required={`${required}`}
         onFocus={this.onFocus}
         onBlur={this.onBlur}
@@ -1067,9 +1120,9 @@ export class Select implements ComponentInterface {
   }
 
   private getHintTextID(): string | undefined {
-    const { el, helperText, errorText, helperTextId, errorTextId } = this;
+    const { helperText, errorText, helperTextId, errorTextId, isInvalid } = this;
 
-    if (el.classList.contains('ion-touched') && el.classList.contains('ion-invalid') && errorText) {
+    if (isInvalid && errorText) {
       return errorTextId;
     }
 
@@ -1084,14 +1137,14 @@ export class Select implements ComponentInterface {
    * Renders the helper text or error text values
    */
   private renderHintText() {
-    const { helperText, errorText, helperTextId, errorTextId } = this;
+    const { helperText, errorText, helperTextId, errorTextId, isInvalid } = this;
 
     return [
-      <div id={helperTextId} class="helper-text" part="supporting-text helper-text">
-        {helperText}
+      <div id={helperTextId} class="helper-text" part="supporting-text helper-text" aria-live="polite">
+        {!isInvalid ? helperText : null}
       </div>,
-      <div id={errorTextId} class="error-text" part="supporting-text error-text">
-        {errorText}
+      <div id={errorTextId} class="error-text" part="supporting-text error-text" role="alert">
+        {isInvalid ? errorText : null}
       </div>,
     ];
   }
@@ -1115,6 +1168,17 @@ export class Select implements ComponentInterface {
     return <div class="select-bottom">{this.renderHintText()}</div>;
   }
 
+  /**
+   * Checks if the input is in an invalid state based
+   * on Ionic validation classes.
+   */
+  private checkInvalidState(): boolean {
+    const hasIonTouched = this.el.classList.contains('ion-touched');
+    const hasIonInvalid = this.el.classList.contains('ion-invalid');
+
+    return hasIonTouched && hasIonInvalid;
+  }
+
   render() {
     const {
       disabled,

core/src/components/select/test/validation/index.html

@@ -0,0 +1,200 @@
+<!DOCTYPE html>
+<html lang="en" dir="ltr">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Select - Validation</title>
+    <meta
+      name="viewport"
+      content="viewport-fit=cover, width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"
+    />
+    <link href="../../../../../css/ionic.bundle.css" rel="stylesheet" />
+    <link href="../../../../../scripts/testing/styles.css" rel="stylesheet" />
+    <script src="../../../../../scripts/testing/scripts.js"></script>
+    <script nomodule src="../../../../../dist/ionic/ionic.js"></script>
+    <script type="module" src="../../../../../dist/ionic/ionic.esm.js"></script>
+    <style>
+      .grid {
+        display: grid;
+        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
+        grid-row-gap: 30px;
+        grid-column-gap: 30px;
+      }
+
+      h2 {
+        font-size: 12px;
+        font-weight: normal;
+
+        color: var(--ion-color-step-600);
+
+        margin-top: 10px;
+        margin-bottom: 5px;
+      }
+
+      .validation-info {
+        margin: 20px;
+        padding: 10px;
+        background: var(--ion-color-light);
+        border-radius: 4px;
+      }
+    </style>
+  </head>
+
+  <body>
+    <ion-app>
+      <ion-header>
+        <ion-toolbar>
+          <ion-title>Select - Validation Test</ion-title>
+        </ion-toolbar>
+      </ion-header>
+
+      <ion-content class="ion-padding">
+        <div class="validation-info">
+          <h2>Screen Reader Testing Instructions:</h2>
+          <ol>
+            <li>Enable your screen reader (VoiceOver, NVDA, JAWS, etc.)</li>
+            <li>Tab through the form fields</li>
+            <li>When you tab away from an empty required field, the error should be announced immediately</li>
+            <li>The error text should be announced BEFORE the next field is announced</li>
+            <li>Test in Chrome, Safari, and Firefox to verify consistent behavior</li>
+          </ol>
+        </div>
+
+        <div class="grid">
+          <div>
+            <h2>Required Field</h2>
+            <ion-select
+              id="fruits-select"
+              label="Fruits"
+              placeholder="Select one"
+              interface="alert"
+              helper-text="You must select an option to continue"
+              error-text="This field is required"
+              required
+            >
+              <ion-select-option value="apples">Apples</ion-select-option>
+              <ion-select-option value="oranges">Oranges</ion-select-option>
+              <ion-select-option value="pears">Pears</ion-select-option>
+            </ion-select>
+          </div>
+
+          <div>
+            <h2>Optional Field (No Validation)</h2>
+            <ion-select
+              id="optional-select"
+              label="Colors"
+              placeholder="Select one"
+              interface="alert"
+              helper-text="You can skip this field"
+            >
+              <ion-select-option value="red">Red</ion-select-option>
+              <ion-select-option value="blue">Blue</ion-select-option>
+              <ion-select-option value="green">Green</ion-select-option>
+            </ion-select>
+          </div>
+        </div>
+
+        <div class="ion-padding">
+          <ion-button id="submit-btn" expand="block" disabled>Submit Form</ion-button>
+          <ion-button id="reset-btn" expand="block" fill="outline">Reset Form</ion-button>
+        </div>
+      </ion-content>
+    </ion-app>
+
+    <script>
+      // Simple validation logic
+      const selects = document.querySelectorAll('ion-select');
+      const submitBtn = document.getElementById('submit-btn');
+      const resetBtn = document.getElementById('reset-btn');
+
+      // Track which fields have been touched
+      const touchedFields = new Set();
+
+      // Validation functions
+      const validators = {
+        'fruits-select': (value) => {
+          return value !== '' && value !== undefined;
+        },
+        'optional-select': () => true, // Always valid
+      };
+
+      function validateField(select) {
+        const selectId = select.id;
+        const value = select.value;
+        const isValid = validators[selectId] ? validators[selectId](value) : true;
+
+        // Only show validation state if field has been touched
+        if (touchedFields.has(selectId)) {
+          if (isValid) {
+            select.classList.remove('ion-invalid');
+            select.classList.add('ion-valid');
+          } else {
+            select.classList.remove('ion-valid');
+            select.classList.add('ion-invalid');
+          }
+          select.classList.add('ion-touched');
+        }
+
+        return isValid;
+      }
+
+      function validateForm() {
+        let allValid = true;
+        selects.forEach((select) => {
+          if (select.id !== 'optional-select') {
+            const isValid = validateField(select);
+            if (!isValid) {
+              allValid = false;
+            }
+          }
+        });
+        submitBtn.disabled = !allValid;
+        return allValid;
+      }
+
+      // Add event listeners
+      selects.forEach((select) => {
+        // Mark as touched on blur
+        select.addEventListener('ionBlur', (e) => {
+          console.log('Blur event on:', select.id);
+          touchedFields.add(select.id);
+          validateField(select);
+          validateForm();
+
+          const isInvalid = select.classList.contains('ion-invalid');
+          if (isInvalid) {
+            console.log('Field marked invalid:', select.label, select.errorText);
+          }
+        });
+
+        // Validate on change
+        select.addEventListener('ionChange', (e) => {
+          console.log('Change event on:', select.id);
+          if (touchedFields.has(select.id)) {
+            validateField(select);
+            validateForm();
+          }
+        });
+      });
+
+      // Reset button
+      resetBtn.addEventListener('click', () => {
+        selects.forEach((select) => {
+          select.value = '';
+          select.classList.remove('ion-valid', 'ion-invalid', 'ion-touched');
+        });
+        touchedFields.clear();
+        submitBtn.disabled = true;
+      });
+
+      // Submit button
+      submitBtn.addEventListener('click', () => {
+        if (validateForm()) {
+          alert('Form submitted successfully!');
+        }
+      });
+
+      // Initial setup
+      validateForm();
+    </script>
+  </body>
+</html>

packages/angular/test/base/src/app/lazy/template-form/template-form.component.html

@@ -77,6 +77,31 @@
           <p>MinLength Errors: <span id="minlength-errors">{{minLengthField.errors | json}}</span></p>
         </ion-label>
       </ion-item>
+
+      <!-- Test ion-select with required validation -->
+      <ion-item>
+        <ion-select
+          label="Required Select"
+          [(ngModel)]="selectValue"
+          name="selectField"
+          required
+          #selectField="ngModel"
+          id="template-select-test"
+          errorText="This field is required"
+          helperText="Select an option">
+          <ion-select-option value="option1">Option 1</ion-select-option>
+          <ion-select-option value="option2">Option 2</ion-select-option>
+        </ion-select>
+      </ion-item>
+      
+      <!-- Display validation state for debugging -->
+      <ion-item>
+        <ion-label>
+          <p>Select Touched: <span id="select-touched">{{selectField.touched}}</span></p>
+          <p>Select Invalid: <span id="select-invalid">{{selectField.invalid}}</span></p>
+          <p>Select Errors: <span id="select-errors">{{selectField.errors | json}}</span></p>
+        </ion-label>
+      </ion-item>
     </ion-list>
 
     <div class="ion-padding">

packages/angular/test/base/src/app/lazy/template-form/template-form.component.ts

@@ -9,6 +9,7 @@ export class TemplateFormComponent {
   inputValue = '';
   textareaValue = '';
   minLengthValue = '';
+  selectValue = '';
 
   // Track if form has been submitted
   submitted = false;