feat: use <picture> element for responsive images @W-18714493

Author: seckardt

packages/template-retail-react-app/app/components/dynamic-image/index.jsx

@@ -1,38 +1,107 @@
 /*
- * Copyright (c) 2021, salesforce.com, inc.
+ * Copyright (c) 2025, Salesforce, Inc.
  * All rights reserved.
  * SPDX-License-Identifier: BSD-3-Clause
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/BSD-3-Clause
  */
 import React, {useMemo} from 'react'
+import {Helmet} from 'react-helmet'
 import PropTypes from 'prop-types'
 import {Box, useTheme} from '@salesforce/retail-react-app/app/components/shared/ui'
-import Image from '@salesforce/retail-react-app/app/components/image'
-import {getResponsiveImageAttributes} from '@salesforce/retail-react-app/app/utils/responsive-image'
+import {Img} from '@salesforce/retail-react-app/app/components/shared/ui'
+import {getResponsivePictureAttributes} from '@salesforce/retail-react-app/app/utils/responsive-image'
+import {
+    getImageAttributes,
+    getImageLinkAttributes
+} from '@salesforce/retail-react-app/app/utils/image'
+import {isServer} from '@salesforce/retail-react-app/app/components/image/utils'
 
 /**
- * Quickly create a responsive image using your Dynamic Imaging Service
+ * Responsive image component optimized to work with the Dynamic Imaging Service.
+ * Via this component it's easy to create a `<picture>` element with related
+ * theme-aware `<source>` elements and responsive preloading for high-priority
+ * images.
  * @example
  *  // Widths without a unit are interpreted as px values
  * <DynamicImage src="http://example.com/image.jpg[?sw={width}&q=60]" widths={[100, 360, 720]} />
  * <DynamicImage src="http://example.com/image.jpg[?sw={width}&q=60]" widths={{base: 100, sm: 360, md: 720}} />
  * // You can also use units of px or vw
  * <DynamicImage src="http://example.com/image.jpg[?sw={width}&q=60]" widths={['50vw', '100vw', '500px']} />
+ * @see {@link https://web.dev/learn/design/responsive-images}
+ * @see {@link https://web.dev/learn/design/picture-element}
+ * @see {@link https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/picture}
+ * @see {@link https://developer.mozilla.org/en-US/docs/Web/HTML/Guides/Responsive_images}
  * @see {@link https://help.salesforce.com/s/articleView?id=cc.b2c_image_transformation_service.htm&type=5}
  */
 const DynamicImage = ({src, widths, densities, imageProps, as, ...rest}) => {
-    const Component = as ? as : Image
+    const Component = as ? as : Img
     const theme = useTheme()
 
-    const responsiveImageProps = useMemo(
-        () =>
-            getResponsiveImageAttributes({src, widths, densities, breakpoints: theme.breakpoints}),
-        [src, widths, densities, theme.breakpoints]
-    )
+    const [responsiveImageProps, l, effectiveImageProps, responsiveLinks] = useMemo(() => {
+        const responsiveImageProps = getResponsivePictureAttributes({
+            src,
+            widths,
+            densities,
+            breakpoints: theme.breakpoints
+        })
+        const l = responsiveImageProps.sources.length
+        const effectiveImageProps = getImageAttributes(imageProps)
+        const fetchPriority = effectiveImageProps.fetchPriority
+        const responsiveLinks =
+            !responsiveImageProps.links.length && fetchPriority === 'high'
+                ? [
+                      getImageLinkAttributes({
+                          ...effectiveImageProps,
+                          fetchPriority, // React <18 vs. >=19 issue
+                          src: responsiveImageProps.src
+                      })
+                  ]
+                : responsiveImageProps.links.reduce((acc, link) => {
+                      const linkProps = getImageLinkAttributes({
+                          ...effectiveImageProps,
+                          ...link,
+                          fetchPriority, // React <18 vs. >=19 issue
+                          src: responsiveImageProps.src
+                      })
+                      if (linkProps) {
+                          acc.push(linkProps)
+                      }
+                      return acc
+                  }, [])
+        return [responsiveImageProps, l, effectiveImageProps, responsiveLinks]
+    }, [src, widths, densities, theme.breakpoints])
 
     return (
         <Box {...rest}>
-            <Component {...responsiveImageProps} {...imageProps} />
+            {l > 0 ? (
+                <picture>
+                    {responsiveImageProps.sources.map(({srcSet, sizes, media, src}, idx) => {
+                        if (idx < l - 1) {
+                            return <source key={idx} media={media} sizes={sizes} srcSet={srcSet} />
+                        }
+                        return (
+                            <Component
+                                key={idx}
+                                {...effectiveImageProps}
+                                sizes={sizes}
+                                srcSet={srcSet}
+                                src={responsiveImageProps.src}
+                            />
+                        )
+                    })}
+                </picture>
+            ) : (
+                <Component {...effectiveImageProps} src={responsiveImageProps.src} />
+            )}
+
+            {isServer() && responsiveLinks.length > 0 && (
+                <Helmet>
+                    {responsiveLinks.map((responsiveLinkProps, idx) => {
+                        const {href, ...rest} = responsiveLinkProps
+                        return <link key={idx} {...rest} href={href} />
+                    })}
+                </Helmet>
+            )}
         </Box>
     )
 }
@@ -49,7 +118,7 @@ DynamicImage.propTypes = {
     /**
      * Image density factors to apply relative to the breakpoints. Will be mapped to the corresponding `srcSet`.
      */
-    densities: PropTypes.array,
+    densities: PropTypes.oneOfType([PropTypes.array, PropTypes.object]),
     /**
      * Props to pass to the inner image component
      */