feat(input, textarea, select): add start and end slots (#28583)

Issue number: Resolves #26297

---------

<!-- Please do not submit updates to dependencies unless it fixes an
issue. -->

<!-- Please try to limit your pull request to one type (bugfix, feature,
etc). Submit multiple pull requests if needed. -->

## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->

With the modern form control syntax, it is not possible to add icon
buttons or other decorators to the sides of `ion-input`, `ion-textarea`,
or `ion-select`, as you can with `ion-item`.

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

`start` and `end` slots added to each component.

This PR is a combination of several others that were already approved.
If needed, it might be easiest to review the PRs individually by looking
at the commit history here.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this introduces a breaking change, please describe the impact
and migration path for existing applications below. -->


## Other information

<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->

Docs PR: ionic-team/ionic-docs#3271

Dev build: `7.5.4-dev.11701112913.1ea61220`

---------

Co-authored-by: ionitron <hi@ionicframework.com>
Co-authored-by: Maria Hutt <thetaPC@users.noreply.github.com>
Co-authored-by: Liam DeBeasi <liamdebeasi@users.noreply.github.com>

core/src/components/input/input.md.outline.scss

@@ -89,9 +89,7 @@
 /**
  * This makes the label sit above the input.
  */
-:host(.has-focus.input-fill-outline.input-label-placement-floating) .label-text-wrapper,
-:host(.has-value.input-fill-outline.input-label-placement-floating) .label-text-wrapper,
-:host(.input-fill-outline.input-label-placement-stacked) .label-text-wrapper {
+:host(.label-floating.input-fill-outline) .label-text-wrapper {
   @include transform(translateY(-32%), scale(#{$form-control-label-stacked-scale}));
   @include margin(0);
 
@@ -216,8 +214,6 @@
  * the floating/stacked label. We simulate this "cut out"
  * by removing the top border from the notch fragment.
  */
-:host(.has-focus.input-fill-outline.input-label-placement-floating) .input-outline-notch,
-:host(.has-value.input-fill-outline.input-label-placement-floating) .input-outline-notch,
-:host(.input-fill-outline.input-label-placement-stacked) .input-outline-notch {
+:host(.label-floating.input-fill-outline) .input-outline-notch {
   border-top: none;
 }

core/src/components/input/input.md.solid.scss

@@ -67,9 +67,7 @@
 // Input Label
 // ----------------------------------------------------------------
 
-:host(.input-fill-solid.input-label-placement-stacked) .label-text-wrapper,
-:host(.has-focus.input-fill-solid.input-label-placement-floating) .label-text-wrapper,
-:host(.has-value.input-fill-solid.input-label-placement-floating) .label-text-wrapper {
+:host(.label-floating.input-fill-solid.input-label-placement-floating) .label-text-wrapper {
   /**
    * Label text should not extend
    * beyond the bounds of the input.

core/src/components/input/input.scss

@@ -322,6 +322,9 @@
 
   flex-grow: 1;
 
+  // ensure start/end slot content is vertically centered
+  align-items: center;
+
   width: 100%;
 }
 
@@ -641,9 +644,7 @@
 /**
  * This makes the label sit above the input.
  */
-:host(.input-label-placement-stacked) .label-text-wrapper,
-:host(.has-focus.input-label-placement-floating) .label-text-wrapper,
-:host(.has-value.input-label-placement-floating) .label-text-wrapper {
+:host(.label-floating) .label-text-wrapper {
   @include transform(translateY(50%), scale(#{$form-control-label-stacked-scale}));
 
   /**
@@ -652,3 +653,14 @@
    */
   max-width: calc(100% / #{$form-control-label-stacked-scale});
 }
+
+// Start/End Slots
+// ----------------------------------------------------------------
+
+::slotted([slot="start"]) {
+  margin-inline-end: $form-control-label-margin;
+}
+
+::slotted([slot="end"]) {
+  margin-inline-start: $form-control-label-margin;
+}

core/src/components/input/input.tsx

@@ -26,6 +26,8 @@ import { getCounterText } from './input.utils';
  * @virtualProp {"ios" | "md"} mode - The mode determines which platform styles to use.
  *
  * @slot label - The label text to associate with the input. Use the `labelPlacement` property to control where the label is placed relative to the input. Use this if you need to render a label with custom HTML. (EXPERIMENTAL)
+ * @slot start - Content to display at the leading edge of the input. (EXPERIMENTAL)
+ * @slot end - Content to display at the trailing edge of the input. (EXPERIMENTAL)
  */
 @Component({
   tag: 'ion-input',
@@ -369,7 +371,7 @@ export class Input implements ComponentInterface {
     const { el } = this;
 
     this.legacyFormController = createLegacyFormController(el);
-    this.slotMutationController = createSlotMutationController(el, 'label', () => forceUpdate(this));
+    this.slotMutationController = createSlotMutationController(el, ['label', 'start', 'end'], () => forceUpdate(this));
     this.notchController = createNotchController(
       el,
       () => this.notchSpacerEl,
@@ -697,18 +699,42 @@ export class Input implements ComponentInterface {
   }
 
   private renderInput() {
-    const { disabled, fill, readonly, shape, inputId, labelPlacement } = this;
+    const { disabled, fill, readonly, shape, inputId, labelPlacement, el, hasFocus } = this;
     const mode = getIonMode(this);
     const value = this.getValue();
     const inItem = hostContext('ion-item', this.el);
     const shouldRenderHighlight = mode === 'md' && fill !== 'outline' && !inItem;
 
+    const hasValue = this.hasValue();
+    const hasStartEndSlots = el.querySelector('[slot="start"], [slot="end"]') !== null;
+
+    /**
+     * If the label is stacked, it should always sit above the input.
+     * For floating labels, the label should move above the input if
+     * the input has a value, is focused, or has anything in either
+     * the start or end slot.
+     *
+     * If there is content in the start slot, the label would overlap
+     * it if not forced to float. This is also applied to the end slot
+     * because with the default or solid fills, the input is not
+     * vertically centered in the container, but the label is. This
+     * causes the slots and label to appear vertically offset from each
+     * other when the label isn't floating above the input. This doesn't
+     * apply to the outline fill, but this was not accounted for to keep
+     * things consistent.
+     *
+     * TODO(FW-5592): Remove hasStartEndSlots condition
+     */
+    const labelShouldFloat =
+      labelPlacement === 'stacked' || (labelPlacement === 'floating' && (hasValue || hasFocus || hasStartEndSlots));
+
     return (
       <Host
         class={createColorClasses(this.color, {
           [mode]: true,
-          'has-value': this.hasValue(),
-          'has-focus': this.hasFocus,
+          'has-value': hasValue,
+          'has-focus': hasFocus,
+          'label-floating': labelShouldFloat,
           [`input-fill-${fill}`]: fill !== undefined,
           [`input-shape-${shape}`]: shape !== undefined,
           [`input-label-placement-${labelPlacement}`]: true,
@@ -717,9 +743,16 @@ export class Input implements ComponentInterface {
           'input-disabled': disabled,
         })}
       >
-        <label class="input-wrapper">
+        {/**
+         * htmlFor is needed so that clicking the label always focuses
+         * the input. Otherwise, if the start slot has something
+         * interactable, clicking the label would focus that instead
+         * since it comes before the input in the DOM.
+         */}
+        <label class="input-wrapper" htmlFor={inputId}>
           {this.renderLabelContainer()}
           <div class="native-wrapper">
+            <slot name="start"></slot>
             <input
               class="native-input"
               ref={(input) => (this.nativeInput = input)}
@@ -774,6 +807,7 @@ export class Input implements ComponentInterface {
                 <ion-icon aria-hidden="true" icon={mode === 'ios' ? closeCircle : closeSharp}></ion-icon>
               </button>
             )}
+            <slot name="end"></slot>
           </div>
           {shouldRenderHighlight && <div class="input-highlight"></div>}
         </label>

core/src/components/input/test/a11y/index.html

@@ -21,7 +21,13 @@ <h1>Input - a11y</h1>
       <ion-input label="Email" label-placement="stacked" value="hi@ionic.io"></ion-input><br />
       <ion-input label="Email" label-placement="floating"></ion-input> <br />
       <ion-input label="Email" label-placement="floating" fill="outline" value="hi@ionic.io"></ion-input> <br />
-      <ion-input label="Email" label-placement="floating" fill="solid" value="hi@ionic.io"></ion-input>
+      <ion-input label="Email" label-placement="floating" fill="solid" value="hi@ionic.io"></ion-input><br />
+      <ion-input label="Email" fill="solid" value="hi@ionic.io">
+        <ion-icon slot="start" name="lock-closed" aria-hidden="true"></ion-icon>
+        <ion-button slot="end" aria-label="button">
+          <ion-icon slot="icon-only" name="lock-closed" aria-hidden="true"></ion-icon>
+        </ion-button>
+      </ion-input>
     </main>
   </body>
 </html>

core/src/components/input/test/slot/index.html

@@ -49,53 +49,125 @@
       </ion-header>
 
       <ion-content id="content" class="ion-padding">
+        <h1>Label Slot</h1>
         <div class="grid">
           <div class="grid-item">
-            <h2>No Fill / Start</h2>
+            <h2>No Fill / Start Label</h2>
             <ion-input label-placement="start" value="hi@ionic.io">
               <div slot="label">Email <span class="required">*</span></div>
             </ion-input>
           </div>
 
           <div class="grid-item">
-            <h2>Solid / Start</h2>
+            <h2>Solid / Start Label</h2>
             <ion-input label-placement="start" fill="solid" value="hi@ionic.io">
               <div slot="label">Email <span class="required">*</span></div>
             </ion-input>
           </div>
 
           <div class="grid-item">
-            <h2>Outline / Start</h2>
+            <h2>Outline / Start Label</h2>
             <ion-input label-placement="start" fill="outline" value="hi@ionic.io">
               <div slot="label">Email <span class="required">*</span></div>
             </ion-input>
           </div>
 
           <div class="grid-item">
-            <h2>No Fill / Floating</h2>
+            <h2>No Fill / Floating Label</h2>
             <ion-input label-placement="floating" value="hi@ionic.io">
               <div slot="label">Email <span class="required">*</span></div>
             </ion-input>
           </div>
 
           <div class="grid-item">
-            <h2>Solid / Floating</h2>
+            <h2>Solid / Floating Label</h2>
             <ion-input label-placement="floating" fill="solid" value="hi@ionic.io">
               <div slot="label">Email <span class="required">*</span></div>
             </ion-input>
           </div>
 
           <div class="grid-item">
-            <h2>Outline / Floating</h2>
+            <h2>Outline / Floating Label</h2>
             <ion-input label-placement="floating" fill="outline" value="hi@ionic.io">
               <div slot="label">Email <span class="required">*</span></div>
             </ion-input>
           </div>
+        </div>
+
+        <h1>Start/End Slots</h1>
+        <div class="grid">
+          <div class="grid-item">
+            <h2>No Fill / Start Label</h2>
+            <ion-input label-placement="start" value="hi@ionic.io" label="Email">
+              <ion-icon slot="start" name="lock-closed" aria-hidden="true"></ion-icon>
+              <ion-button fill="clear" slot="end" aria-label="Show/hide password">
+                <ion-icon slot="icon-only" name="eye" aria-hidden="true"></ion-icon>
+              </ion-button>
+            </ion-input>
+          </div>
 
           <div class="grid-item">
-            <h2>Outline / Floating / Async</h2>
+            <h2>Solid / Start Label</h2>
+            <ion-input label-placement="start" fill="solid" value="hi@ionic.io" label="Email">
+              <ion-icon slot="start" name="lock-closed" aria-hidden="true"></ion-icon>
+              <ion-button fill="clear" slot="end" aria-label="Show/hide password">
+                <ion-icon slot="icon-only" name="eye" aria-hidden="true"></ion-icon>
+              </ion-button>
+            </ion-input>
+          </div>
+
+          <div class="grid-item">
+            <h2>Outline / Start Label</h2>
+            <ion-input label-placement="start" fill="outline" value="hi@ionic.io" label="Email">
+              <ion-icon slot="start" name="lock-closed" aria-hidden="true"></ion-icon>
+              <ion-button fill="clear" slot="end" aria-label="Show/hide password">
+                <ion-icon slot="icon-only" name="eye" aria-hidden="true"></ion-icon>
+              </ion-button>
+            </ion-input>
+          </div>
+
+          <div class="grid-item">
+            <h2>No Fill / Floating Label</h2>
+            <ion-input label-placement="floating" value="hi@ionic.io" label="Email">
+              <ion-icon slot="start" name="lock-closed" aria-hidden="true"></ion-icon>
+              <ion-button fill="clear" slot="end" aria-label="Show/hide password">
+                <ion-icon slot="icon-only" name="eye" aria-hidden="true"></ion-icon>
+              </ion-button>
+            </ion-input>
+          </div>
+
+          <div class="grid-item">
+            <h2>Solid / Floating Label</h2>
+            <ion-input label-placement="floating" fill="solid" value="hi@ionic.io" label="Email">
+              <ion-icon slot="start" name="lock-closed" aria-hidden="true"></ion-icon>
+              <ion-button fill="clear" slot="end" aria-label="Show/hide password">
+                <ion-icon slot="icon-only" name="eye" aria-hidden="true"></ion-icon>
+              </ion-button>
+            </ion-input>
+          </div>
+
+          <div class="grid-item">
+            <h2>Outline / Floating Label</h2>
+            <ion-input label-placement="floating" fill="outline" value="hi@ionic.io" label="Email">
+              <ion-icon slot="start" name="lock-closed" aria-hidden="true"></ion-icon>
+              <ion-button fill="clear" slot="end" aria-label="Show/hide password">
+                <ion-icon slot="icon-only" name="eye" aria-hidden="true"></ion-icon>
+              </ion-button>
+            </ion-input>
+          </div>
+        </div>
+
+        <h1>Async Slot Content</h1>
+        <div class="grid">
+          <div class="grid-item">
+            <h2>Outline / Async Label</h2>
             <ion-input id="solid-async" label-placement="floating" fill="outline" value="hi@ionic.io"></ion-input>
           </div>
+
+          <div class="grid-item">
+            <h2>Outline / Async Decorations</h2>
+            <ion-input id="async-decorations" label-placement="floating" fill="outline" label="Email"></ion-input>
+          </div>
         </div>
 
         <ion-button onclick="addSlot()">Add Slotted Content</ion-button>
@@ -106,29 +178,65 @@ <h2>Outline / Floating / Async</h2>
 
     <script>
       const solidAsync = document.querySelector('#solid-async');
+      const asyncDecos = document.querySelector('#async-decorations');
 
-      const getSlottedContent = () => {
+      const getSlottedLabel = () => {
         return solidAsync.querySelector('[slot="label"]');
       };
 
+      const getSlottedStartDeco = () => {
+        return asyncDecos.querySelector('[slot="start"]');
+      };
+
+      const getSlottedEndDeco = () => {
+        return asyncDecos.querySelector('[slot="end"]');
+      };
+
       const addSlot = () => {
-        if (getSlottedContent() === null) {
+        if (getSlottedLabel() === null) {
           const labelEl = document.createElement('div');
           labelEl.slot = 'label';
           labelEl.innerHTML = 'Email <span class="required">*</span>';
 
           solidAsync.appendChild(labelEl);
         }
+
+        if (getSlottedStartDeco() === null) {
+          const startEl = document.createElement('div');
+          startEl.slot = 'start';
+          startEl.innerHTML = 'Start';
+
+          asyncDecos.insertAdjacentElement('afterbegin', startEl);
+        }
+
+        if (getSlottedEndDeco() === null) {
+          const endEl = document.createElement('div');
+          endEl.slot = 'end';
+          endEl.innerHTML = 'End';
+
+          asyncDecos.insertAdjacentElement('beforeend', endEl);
+        }
       };
 
       const removeSlot = () => {
-        if (getSlottedContent() !== null) {
-          solidAsync.querySelector('[slot="label"]').remove();
+        const slottedLabel = getSlottedLabel();
+        if (slottedLabel !== null) {
+          slottedLabel.remove();
+        }
+
+        const slottedStartDeco = getSlottedStartDeco();
+        if (slottedStartDeco !== null) {
+          slottedStartDeco.remove();
+        }
+
+        const slottedEndDeco = getSlottedEndDeco();
+        if (slottedEndDeco !== null) {
+          slottedEndDeco.remove();
         }
       };
 
       const updateSlot = () => {
-        const slottedContent = getSlottedContent();
+        const slottedContent = getSlottedLabel();
 
         if (slottedContent !== null) {
           slottedContent.textContent = 'This is my really really really long text';