fix(textarea): textarea with autogrow will size to its contents

core/src/components.d.ts

@@ -2803,7 +2803,7 @@ export namespace Components {
     }
     interface IonTextarea {
         /**
-          * If `true`, the element height will increase based on the value.
+          * If `true`, the textarea container will grow and shrink based on the contents of the textarea.
          */
         "autoGrow": boolean;
         /**
@@ -6786,7 +6786,7 @@ declare namespace LocalJSX {
     }
     interface IonTextarea {
         /**
-          * If `true`, the element height will increase based on the value.
+          * If `true`, the textarea container will grow and shrink based on the contents of the textarea.
          */
         "autoGrow"?: boolean;
         /**

core/src/components/textarea/test/autogrow/textarea.e2e.ts

@@ -2,11 +2,9 @@ import { expect } from '@playwright/test';
 import { test } from '@utils/test/playwright';
 
 test.describe('textarea: autogrow', () => {
-  test.skip('should not have visual regressions', async ({ page }) => {
+  test('should not have visual regressions', async ({ page }) => {
     await page.goto(`/src/components/textarea/test/autogrow`);
 
-    await page.waitForChanges();
-
     await page.setIonViewport();
 
     expect(await page.screenshot()).toMatchSnapshot(`textarea-autogrow-diff-${page.getSnapshotSettings()}.png`);

core/src/components/textarea/test/basic/index.html

@@ -67,12 +67,6 @@
             <ion-label color="primary">Clear on Edit</ion-label>
             <ion-textarea clear-on-edit="true"></ion-textarea>
           </ion-item>
-
-          <!-- TODO: Re-add auto grow with PR#24205 -->
-          <!-- <ion-item>
-            <ion-label color="primary">Autogrow</ion-label>
-            <ion-textarea auto-grow="true"></ion-textarea>
-          </ion-item> -->
         </ion-list>
 
         <div class="ion-text-center">

core/src/components/textarea/textarea.scss

@@ -26,7 +26,7 @@
   --placeholder-color: initial;
   --placeholder-font-style: initial;
   --placeholder-font-weight: initial;
-  --placeholder-opacity: .5;
+  --placeholder-opacity: 0.5;
   --padding-top: 0;
   --padding-end: 0;
   --padding-bottom: 0;
@@ -71,22 +71,41 @@
   --padding-start: 0;
 }
 
-
 // Native Textarea
 // --------------------------------------------------
 
 .textarea-wrapper {
+  display: grid;
+
   min-width: inherit;
   max-width: inherit;
   min-height: inherit;
   max-height: inherit;
+
+  &::after {
+    // This technique is used for an auto-resizing textarea.
+    // The text contents are reflected as a pseudo-element that is visually hidden.
+    // This causes the textarea container to grow as needed to fit the contents.
+
+    white-space: pre-wrap;
+
+    content: attr(data-replicated-value) " ";
+
+    visibility: hidden;
+  }
+}
+
+.native-textarea,
+.textarea-wrapper::after {
+  @include padding(var(--padding-top), var(--padding-end), var(--padding-bottom), var(--padding-start));
+  @include text-inherit();
+
+  grid-area: 1 / 1 / 2 / 2;
 }
 
 .native-textarea {
   @include border-radius(var(--border-radius));
   @include margin(0);
-  @include padding(var(--padding-top), var(--padding-end), var(--padding-bottom), var(--padding-start));
-  @include text-inherit();
 
   display: block;
 
@@ -103,6 +122,8 @@
   resize: none;
   appearance: none;
 
+  overflow: hidden;
+
   &::placeholder {
     @include padding(0);
 
@@ -117,7 +138,7 @@
 }
 
 .native-textarea[disabled] {
-  opacity: .4;
+  opacity: 0.4;
 }
 
 // Input Cover: Unfocused
@@ -136,6 +157,15 @@
   pointer-events: none;
 }
 
+:host([auto-grow]) .cloned-input {
+  // Workaround for webkit rendering issue with scroll assist.
+  // When cloning the textarea and scrolling into view,
+  // a white box is rendered from the difference in height
+  // from the auto grow container.
+  // This change forces the cloned input to match the true
+  // height of the textarea container. 
+  height: 100%;
+}
 
 // Item Floating: Placeholder
 // ----------------------------------------------------------------

core/src/components/textarea/textarea.tsx

@@ -1,10 +1,10 @@
 import type { ComponentInterface, EventEmitter } from '@stencil/core';
-import { Build, Component, Element, Event, Host, Method, Prop, State, Watch, h, readTask } from '@stencil/core';
+import { Build, Component, Element, Event, Host, Method, Prop, State, Watch, h, writeTask } from '@stencil/core';
 
 import { getIonMode } from '../../global/ionic-global';
 import type { Color, StyleEventDetail, TextareaChangeEventDetail } from '../../interface';
 import type { Attributes } from '../../utils/helpers';
-import { inheritAriaAttributes, debounceEvent, findItemLabel, inheritAttributes, raf } from '../../utils/helpers';
+import { inheritAriaAttributes, debounceEvent, findItemLabel, inheritAttributes } from '../../utils/helpers';
 import { createColorClasses } from '../../utils/theme';
 
 /**
@@ -147,9 +147,10 @@ export class Textarea implements ComponentInterface {
   @Prop() wrap?: 'hard' | 'soft' | 'off';
 
   /**
-   * If `true`, the element height will increase based on the value.
+   * If `true`, the textarea container will grow and shrink based
+   * on the contents of the textarea.
    */
-  @Prop() autoGrow = false;
+  @Prop({ reflect: true }) autoGrow = false;
 
   /**
    * The value of the textarea.
@@ -227,20 +228,7 @@ export class Textarea implements ComponentInterface {
   }
 
   componentDidLoad() {
-    raf(() => this.runAutoGrow());
-  }
-
-  private runAutoGrow() {
-    const nativeInput = this.nativeInput;
-    if (nativeInput && this.autoGrow) {
-      readTask(() => {
-        nativeInput.style.height = 'auto';
-        nativeInput.style.height = nativeInput.scrollHeight + 'px';
-        if (this.textareaWrapper) {
-          this.textareaWrapper.style.height = nativeInput.scrollHeight + 'px';
-        }
-      });
-    }
+    this.runAutoGrow();
   }
 
   /**
@@ -286,6 +274,18 @@ export class Textarea implements ComponentInterface {
     });
   }
 
+  private runAutoGrow() {
+    if (this.nativeInput && this.autoGrow) {
+      writeTask(() => {
+        if (this.textareaWrapper) {
+          // Replicated value is an attribute to be used in the stylesheet
+          // to set the inner contents of a pseudo element.
+          this.textareaWrapper.dataset.replicatedValue = this.value ?? '';
+        }
+      });
+    }
+  }
+
   /**
    * Check if we need to clear the text input if clearOnEdit is enabled
    */