Fix thumbnail reuse (#86)

* Fix thumbnail reuse in PDP when no media present

Without any media present on component mount the only image will be
the thumbnail itself. Make sure the `load` event listener is only added
to the first image that is not the thumbnail.

* Remove unused onLoad prop

This didn't work with neither magnified or regular image components.
Thumbnail reuse works through the image selector ref.

* Bump version

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-storefront",
-  "version": "8.3.0",
+  "version": "8.3.1",
   "description": "Build and deploy e-commerce progressive web apps (PWAs) in record time.",
   "module": "./index.js",
   "license": "Apache-2.0",

src/carousel/MediaCarousel.js

@@ -13,6 +13,8 @@ import MagnifyHint from './MagnifyHint'
 import CarouselThumbnails from './CarouselThumbnails'
 import get from 'lodash/get'
 
+const THUMBNAIL_IMAGE_ID = '__rsf-placeholder-thumbnail'
+
 export const styles = theme => ({
   /**
    * Styles applied to the root component.
@@ -198,18 +200,26 @@ function MediaCarousel(props) {
   })
 
   useEffect(() => {
+    if (!ref.current || imagesLoaded || !thumbnail) return
     const firstImage = ref.current.querySelector('img')
-
-    if (firstImage) {
+    if (firstImage && firstImage.id !== THUMBNAIL_IMAGE_ID) {
       firstImage.addEventListener('load', onFullSizeImagesLoaded)
       return () => firstImage.removeEventListener('load', onFullSizeImagesLoaded)
     }
-  }, [])
+  }, [media, imagesLoaded, thumbnail])
 
   const belowAdornments = []
 
   if (thumbnail && !imagesLoaded) {
-    belowAdornments.push(<Image key="thumbnail" className={styles.thumbnail} fill {...thumbnail} />)
+    belowAdornments.push(
+      <Image
+        id={THUMBNAIL_IMAGE_ID}
+        key="thumbnail"
+        className={styles.thumbnail}
+        fill
+        {...thumbnail}
+      />,
+    )
   }
 
   if (media && media.full && media.full.some(item => item.magnify)) {
@@ -278,7 +288,6 @@ function MediaCarousel(props) {
           media.full.map((item, i) => (
             <Fill height="100%" key={i}>
               <MediaComponent
-                onLoad={i === 0 ? onFullSizeImagesLoaded : null}
                 magnifyProps={magnifyProps}
                 {...item}
                 src={get(item, 'magnify.src', item.src)}

test/carousel/MediaCarousel.test.js

@@ -228,6 +228,15 @@ describe('MediaCarousel', () => {
     loadMock.mockClear()
   })
 
+  it('should not add img listener if the only image is the preview thumbnail', async () => {
+    const loadMock = jest.spyOn(HTMLImageElement.prototype, 'addEventListener')
+
+    wrapper = mount(<MediaCarousel thumbnails={false} thumbnail={{ test: 'test' }} />)
+
+    expect(loadMock).not.toBeCalled()
+    loadMock.mockClear()
+  })
+
   it('should have timeout on magnifying carousel', async () => {
     wrapper = mount(<MediaCarousel media={media} />)