fix multiple identical spritesheet icons not applying mutator

docs/pages/resources/changelog.md

@@ -12,6 +12,10 @@ Components with the <sl-badge variant="warning" pill>Experimental</sl-badge> bad
 
 New versions of Shoelace are released as-needed and generally occur when a critical mass of changes have accumulated. At any time, you can see what's coming in the next release by visiting [next.shoelace.style](https://next.shoelace.style).
 
+## Next
+
+- Fixed a bug in `<sl-icon>` not applying the mutator when loading multiple icons of the same name from a spritesheet. [#2178]
+
 ## 2.17.0
 
 - Added the `fixed-scroll-controls` attribute to `<sl-tab-group>` [#2128]

src/components/icon/icon.component.ts

@@ -46,16 +46,6 @@ export default class SlIcon extends ShoelaceElement {
         <use part="use" href="${url}"></use>
       </svg>`;
 
-      // Using a templateResult requires the SVG to be written to the DOM first before we can grab the SVGElement
-      // to be passed to the library's mutator function.
-      await this.updateComplete;
-
-      const svg = this.shadowRoot!.querySelector("[part='svg']")!;
-
-      if (typeof library.mutator === 'function') {
-        library.mutator(svg as SVGElement);
-      }
-
       return this.svg;
     }
 
@@ -185,6 +175,19 @@ export default class SlIcon extends ShoelaceElement {
 
     if (isTemplateResult(svg)) {
       this.svg = svg;
+
+      if (library) {
+        // Using a templateResult requires the SVG to be written to the DOM first before we can grab the SVGElement
+        // to be passed to the library's mutator function.
+        await this.updateComplete;
+
+        const shadowSVG = this.shadowRoot!.querySelector("[part='svg']")!;
+
+        if (typeof library.mutator === 'function' && shadowSVG) {
+          library.mutator(shadowSVG as SVGElement);
+        }
+      }
+
       return;
     }
 

src/components/icon/icon.test.ts

@@ -185,6 +185,34 @@ describe('<sl-icon>', () => {
       expect(rect?.width).to.be.greaterThan(0);
     });
 
+    // https://github.com/shoelace-style/shoelace/issues/2161
+    it('Should apply mutator to multiple identical spritesheet icons', async () => {
+      registerIconLibrary('sprite', {
+        resolver: name => `/docs/assets/images/sprite.svg#${name}`,
+        mutator: svg => svg.setAttribute('fill', 'pink'),
+        spriteSheet: true
+      });
+
+      const el = await fixture<HTMLDivElement>(html`
+        <div>
+          <sl-icon name="arrow-left" library="sprite"></sl-icon>
+          <sl-icon name="arrow-left" library="sprite"></sl-icon>
+        </div>
+      `);
+
+      const icons = [...el.querySelectorAll<SlIcon>('sl-icon')];
+
+      await Promise.allSettled(icons.map(el => elementUpdated(el)));
+
+      // This is kind of hacky...but with no way to check "load", we just use a timeout
+      await aTimeout(1000);
+      const icon1 = icons[0];
+      const icon2 = icons[1];
+
+      expect(icon1.shadowRoot?.querySelector('svg')?.getAttribute('fill')).to.equal('pink');
+      expect(icon2.shadowRoot?.querySelector('svg')?.getAttribute('fill')).to.equal('pink');
+    });
+
     it('Should render nothing if the sprite hash is wrong', async () => {
       registerIconLibrary('sprite', {
         resolver: name => `/docs/assets/images/sprite.svg#${name}`,