fix(range): emit ionInput when value changes (#30293)

Issue number: resolves #29619 

---------

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issue. -->

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etc). Submit multiple pull requests if needed. -->

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

The `ionInput` emits for range even when the value hasn't changed. This
does not match our documentation. It should only emit when the value
changes (and continuously while the user is dragging the knob).

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

- Moved the emitter to the value watch function, to determine if the
value has changed.
- Added a test
-

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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  2. Update the BREAKING.md file with the breaking change.
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## Other information

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

How to test:
1. Navigate to the [range basic HTML
file](8ed08fcba5/core/src/components/range/test/basic/index.html (L77))
2. Add the following script
```
const ionicRanges = document.querySelectorAll('ion-range');

ionicRanges.forEach(range => {  
  range.addEventListener('ionInput', function(ev) {
    console.log('ionInput', ev.currentTarget.value);
  });
});
```
3. Navigate to the [range test
page](http://localhost:3333/src/components/range/test/basic)
4. Open the console
5. Move the single knob range (let go when you're done)
6. Verify that the value is shown in the console
7. Tap as close to the middle of the knob. The goal is to tap it without
the value moving.
8. Verify that the value does not show in the console

---------

Co-authored-by: Brandy Smith <brandyscarney@users.noreply.github.com>

core/src/components/range/range.tsx

@@ -213,12 +213,32 @@ export class Range implements ComponentInterface {
    */
   @Prop({ mutable: true }) value: RangeValue = 0;
   @Watch('value')
-  protected valueChanged() {
+  protected valueChanged(newValue: RangeValue, oldValue: RangeValue) {
+    const valuesChanged = this.compareValues(newValue, oldValue);
+    if (valuesChanged) {
+      this.ionInput.emit({ value: this.value });
+    }
+
     if (!this.noUpdate) {
       this.updateRatio();
     }
   }
 
+  /**
+   * Compares two RangeValue inputs to determine if they are different.
+   *
+   * @param newVal - The new value.
+   * @param oldVal - The old value.
+   * @returns `true` if the values are different, `false` otherwise.
+   */
+  private compareValues = (newVal: RangeValue, oldVal: RangeValue) => {
+    if (typeof newVal === 'object' && typeof oldVal === 'object') {
+      return newVal.lower !== oldVal.lower || newVal.upper !== oldVal.upper;
+    }
+
+    return newVal !== oldVal;
+  };
+
   private clampBounds = (value: any): number => {
     return clamp(this.min, value, this.max);
   };
@@ -591,8 +611,6 @@ export class Range implements ComponentInterface {
           upper: Math.max(valA, valB),
         };
 
-    this.ionInput.emit({ value: this.value });
-
     this.noUpdate = false;
   }
 

core/src/components/range/test/range-events.e2e.ts

@@ -217,6 +217,42 @@ configs({ modes: ['ios'], directions: ['ltr'] }).forEach(({ title, config }) =>
         expect(ionInputSpy).toHaveReceivedEvent();
       });
 
+      test('should not emit when the value does not change', async ({ page }, testInfo) => {
+        testInfo.annotations.push({
+          type: 'issue',
+          description: 'https://github.com/ionic-team/ionic-framework/issues/29619',
+        });
+
+        /**
+         * Requires padding to prevent the knob from being clipped.
+         * If it's clipped, then the value might be one off.
+         * For example, if the knob is clipped on the right, then the value
+         * will be 99 instead of 100.
+         */
+        await page.setContent(
+          `
+          <div style="padding: 0 20px">
+            <ion-range aria-label="range"></ion-range>
+          </div>
+        `,
+          config
+        );
+
+        const rangeHandle = page.locator('ion-range .range-knob-handle');
+        const ionInputSpy = await page.spyOnEvent('ionInput');
+
+        const rangeHandleBoundingBox = await rangeHandle.boundingBox();
+        const x = rangeHandleBoundingBox!.width / 2;
+        const y = rangeHandleBoundingBox!.height / 2;
+
+        // Click in the middle of the knob to prevent the knob from moving.
+        await rangeHandle.click({
+          position: { x, y },
+        });
+
+        expect(ionInputSpy).not.toHaveReceivedEvent();
+      });
+
       test('should emit when the knob is moved with the keyboard', async ({ page }) => {
         await page.setContent(`<ion-range aria-label="range" value="50"></ion-range>`, config);