fix(input): title attribute is automatically inherited (#22493)

resolves #22055

core/src/components/input/input.tsx

@@ -2,7 +2,7 @@ import { Build, Component, ComponentInterface, Element, Event, EventEmitter, Hos
 
 import { getIonMode } from '../../global/ionic-global';
 import { AutocompleteTypes, Color, InputChangeEventDetail, StyleEventDetail, TextFieldTypes } from '../../interface';
-import { debounceEvent, findItemLabel } from '../../utils/helpers';
+import { debounceEvent, findItemLabel, inheritAttributes } from '../../utils/helpers';
 import { createColorClasses } from '../../utils/theme';
 
 /**
@@ -21,7 +21,7 @@ export class Input implements ComponentInterface {
   private nativeInput?: HTMLInputElement;
   private inputId = `ion-input-${inputIds++}`;
   private didBlurAfterEdit = false;
-  private tabindex?: string | number;
+  private inheritedAttributes: { [k: string]: any } = {};
 
   /**
    * This is required for a WebKit bug which requires us to
@@ -225,14 +225,7 @@ export class Input implements ComponentInterface {
   @Event() ionStyle!: EventEmitter<StyleEventDetail>;
 
   componentWillLoad() {
-    // If the ion-input has a tabindex attribute we get the value
-    // and pass it down to the native input, then remove it from the
-    // ion-input to avoid causing tabbing twice on the same element
-    if (this.el.hasAttribute('tabindex')) {
-      const tabindex = this.el.getAttribute('tabindex');
-      this.tabindex = tabindex !== null ? tabindex : undefined;
-      this.el.removeAttribute('tabindex');
-    }
+    this.inheritedAttributes = inheritAttributes(this.el, ['tabindex', 'title']);
   }
 
   connectedCallback() {
@@ -428,13 +421,13 @@ export class Input implements ComponentInterface {
           spellcheck={this.spellcheck}
           step={this.step}
           size={this.size}
-          tabindex={this.tabindex}
           type={this.type}
           value={value}
           onInput={this.onInput}
           onBlur={this.onBlur}
           onFocus={this.onFocus}
           onKeyDown={this.onKeydown}
+          {...this.inheritedAttributes}
         />
         {(this.clearInput && !this.readonly && !this.disabled) && <button
           aria-label="reset"

core/src/components/textarea/textarea.tsx

@@ -2,7 +2,7 @@ import { Build, Component, ComponentInterface, Element, Event, EventEmitter, Hos
 
 import { getIonMode } from '../../global/ionic-global';
 import { Color, StyleEventDetail, TextareaChangeEventDetail } from '../../interface';
-import { debounceEvent, findItemLabel, raf } from '../../utils/helpers';
+import { debounceEvent, findItemLabel, inheritAttributes, raf } from '../../utils/helpers';
 import { createColorClasses } from '../../utils/theme';
 
 /**
@@ -22,6 +22,7 @@ export class Textarea implements ComponentInterface {
   private inputId = `ion-textarea-${textareaIds++}`;
   private didBlurAfterEdit = false;
   private textareaWrapper?: HTMLElement;
+  private inheritedAttributes: { [k: string]: any } = {};
 
   /**
    * This is required for a WebKit bug which requires us to
@@ -212,6 +213,10 @@ export class Textarea implements ComponentInterface {
     }
   }
 
+  componentWillLoad() {
+    this.inheritedAttributes = inheritAttributes(this.el, ['title']);
+  }
+
   componentDidLoad() {
     raf(() => this.runAutoGrow());
   }
@@ -379,6 +384,7 @@ export class Textarea implements ComponentInterface {
             onBlur={this.onBlur}
             onFocus={this.onFocus}
             onKeyDown={this.onKeyDown}
+            {...this.inheritedAttributes}
           >
             {value}
           </textarea>

core/src/utils/helpers.ts

@@ -5,6 +5,32 @@ import { Side } from '../interface';
 declare const __zone_symbol__requestAnimationFrame: any;
 declare const requestAnimationFrame: any;
 
+/**
+ * Elements inside of web components sometimes need to inherit global attributes
+ * set on the host. For example, the inner input in `ion-input` should inherit
+ * the `title` attribute that developers set directly on `ion-input`. This
+ * helper function should be called in componentWillLoad and assigned to a variable
+ * that is later used in the render function.
+ *
+ * This does not need to be reactive as changing attributes on the host element
+ * does not trigger a re-render.
+ */
+export const inheritAttributes = (el: HTMLElement, attributes: string[] = []) => {
+  const attributeObject: { [k: string]: any } = {};
+
+  attributes.forEach(attr => {
+    if (el.hasAttribute(attr)) {
+      const value = el.getAttribute(attr);
+      if (value !== null) {
+        attributeObject[attr] = el.getAttribute(attr);
+      }
+      el.removeAttribute(attr);
+    }
+  });
+
+  return attributeObject;
+}
+
 export const addEventListener = (el: any, eventName: string, callback: any, opts?: any) => {
   if (typeof (window as any) !== 'undefined') {
     const win = window as any;

core/src/utils/test/attributes.spec.ts

@@ -0,0 +1,39 @@
+import { inheritAttributes } from '../helpers';
+
+describe('inheritAttributes()', () => {
+  it('should create an attribute inheritance object', () => {
+    const el = document.createElement('div');
+    el.setAttribute('tabindex', '20');
+    el.setAttribute('title', 'myTitle');
+
+    const attributeObject = inheritAttributes(el, ['tabindex', 'title']);
+
+    expect(attributeObject).toEqual({
+      tabindex: '20',
+      title: 'myTitle'
+    });
+  });
+
+  it('should not inherit attributes that are not defined on the element', () => {
+    const el = document.createElement('div');
+    el.setAttribute('tabindex', '20');
+
+    const attributeObject = inheritAttributes(el, ['tabindex', 'title']);
+
+    expect(attributeObject).toEqual({
+      tabindex: '20'
+    });
+  });
+
+  it('should not inherit attributes that are not defined on the input array', () => {
+    const el = document.createElement('div');
+    el.setAttribute('tabindex', '20');
+    el.setAttribute('title', 'myTitle');
+
+    const attributeObject = inheritAttributes(el, ['title']);
+
+    expect(attributeObject).toEqual({
+      title: 'myTitle'
+    });
+  });
+});