fix(rating): Value rounding calculation when step is 1 (#1551)

Closes #1548

Author: rkaraivanov

CHANGELOG.md

@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - #### Dialog
   - A new `message` slot that renders text content inside the dialog component has been added. The enhancement was introduced to align the design behavior between Ignite UI for WC and Ignite UI for Angular, ensuring a consistent user experience across products. The newly added `message' slot comes with additional styling with a max-width of 40 characters. The default slot is also still available for rendering content inside the dialog without limiting the component's width.
 
+### Fixed
+- #### Rating
+  - Inaccurate value calculation on selection when step is set to 1 [#1548](https://github.com/IgniteUI/igniteui-webcomponents/issues/1548)
+
 ## [5.2.0] - 2025-01-09
 ### Added
 - Form-associated elements now have a `defaultValue` property (`defaultChecked` for radio buttons, checkboxes, and switches). When a form is reset, components will use this property’s value as their new value or checked state.

src/components/common/util.ts

@@ -16,7 +16,7 @@ export const clamp = (number: number, min: number, max: number) =>
   Math.max(min, Math.min(number, max));
 
 export function numberOfDecimals(number: number): number {
-  const decimals = last(number.toString().split('.'));
+  const [_, decimals] = number.toString().split('.');
   return decimals ? decimals.length : 0;
 }
 

src/components/rating/rating.spec.ts

@@ -306,6 +306,18 @@ describe('Rating component', () => {
       expect(el.value).to.equal(2.5);
     });
 
+    it('issue-1548 - Inaccurate value calculation when precision == 1', async () => {
+      const eventSpy = spy(el, 'emitEvent');
+
+      const symbol = getRatingSymbols(el).item(2);
+      const { x, width } = getBoundingRect(symbol);
+      // Simulate offset click when precision == 1
+      simulateClick(symbol, { clientX: x + width / 4 });
+
+      expect(eventSpy).calledOnceWithExactly('igcChange', { detail: 3 });
+      expect(el.value).to.equal(3);
+    });
+
     it('correctly reflects hover state', async () => {
       const eventSpy = spy(el, 'emitEvent');
       el.value = 2;