Improve accessibility with ratio breakpoints & LazyImage component

apps/front/src/components/lazyImage/LazyImage.module.scss

@@ -9,3 +9,21 @@
 :global(.lazyloaded) {
   opacity: 1;
 }
+
+.imageWrapper {
+  position: relative;
+  width: 100%;
+  height: 0;
+}
+
+.image {
+  position: absolute;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+  &:global(.lazyJs) {
+    opacity: 0;
+  }
+}

apps/front/src/components/lazyImage/LazyImage.tsx

@@ -8,15 +8,19 @@ interface IProps {
   dataSrcSet?: string
   className?: string
   alt?: string
-  aspectRatio?: number
   style?: CSSProperties
+  aspectRatio?: string // ex: "16/9" "4/3"
+  width: number
+  height: number
   onLoaded?: (img: HTMLImageElement) => void
 }
 
 export type Lazy = "lazyload" | "lazyloading" | "lazyloaded"
 
 /**
  * @name LazyImage
+ * @description Lazy load image component with srcset and src fallback
+ * @example <LazyImage dataSrcSet="image-600 600w, image-800 800w, image-1024 1024w" src="image-800" alt="image" width={800} height={600} aspectRatio={"4 / 3"} />
  */
 function LazyImage(props: IProps) {
   const imageRef = useRef<HTMLImageElement>(null)
@@ -30,8 +34,7 @@ function LazyImage(props: IProps) {
     new Promise((resolve) => {
       const dataSrc = image.dataset.src
       const dataSrcSet = image.dataset.srcset
-      // create void image tag for start preload
-      // const img = document.createElement("img")
+
       if (dataSrc) image.src = dataSrc
       if (dataSrcSet) image.srcset = dataSrcSet
 
@@ -51,6 +54,21 @@ function LazyImage(props: IProps) {
   const lazyStateRef = useRef<Lazy>("lazyload")
 
   useEffect(() => {
+    // if img lazy is supported by the browser we don't need to use IntersectionObserver
+    if ("loading" in HTMLImageElement.prototype) {
+      // add src and srcset to image
+      if (imageRef.current) {
+        imageRef.current.srcset = props.dataSrcSet ?? ""
+        imageRef.current.src = props.src && !props.dataSrcSet ? props.src : ""
+      }
+      return
+    }
+
+    // add class lazyJs on imageRef
+    if (imageRef.current) {
+      imageRef.current.classList.add("lazyJs")
+    }
+
     const observer = new IntersectionObserver((entries) => {
       entries.forEach(async (entry) => {
         if (entry.isIntersecting) {
@@ -62,6 +80,9 @@ function LazyImage(props: IProps) {
           // Start preload
           await preloadImage(image)
 
+          // Set new src fallback
+          image.src = props.src ?? "data:,"
+
           // end!
           setLazyState("lazyloaded")
           props.onLoaded?.(image)
@@ -76,19 +97,43 @@ function LazyImage(props: IProps) {
     }
   }, [])
 
+  const aspectRatioPadding =
+    props.width && props.height ? (props.height / props.width) * 100 : 0
+
   return (
-    <img
-      ref={imageRef}
-      className={cls(css.root, props.className, lazyState)}
-      src={props.src ?? "data:,"}
-      data-src={props?.dataSrc}
-      data-srcset={props?.dataSrcSet}
-      alt={props?.alt}
-      style={{
-        ...(props.aspectRatio ? { aspectRatio: `${props.aspectRatio}` } : {}),
-        ...(props.style || {})
-      }}
-    />
+    <>
+      <div
+        className={cls(css.imageWrapper, props.className)}
+        style={{
+          paddingBottom: props.aspectRatio
+            ? `calc((2 - ${props.aspectRatio})* 100%)`
+            : `${aspectRatioPadding}%`
+        }}
+      >
+        <img
+          ref={imageRef}
+          className={cls(css.image, lazyState)}
+          src={"data:,"}
+          data-src={props?.dataSrc}
+          data-srcset={props?.dataSrcSet}
+          alt={props?.alt ?? ""}
+          width={props.width}
+          height={props.height}
+          style={props.style}
+          loading={"lazy"}
+        />
+      </div>
+      <noscript>
+        <img
+          className={cls(css.image, props.className)}
+          src={props.src}
+          srcSet={props.dataSrcSet}
+          alt={props.alt}
+          width={props.width}
+          height={props.height}
+        />
+      </noscript>
+    </>
   )
 }
 

apps/front/src/index-server.tsx

@@ -55,7 +55,7 @@ export async function render(
       <head>
         <meta charSet="UTF-8" />
         <meta httpEquiv="x-ua-compatible" content="IE=Edge" />
-        <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1" />
+        <meta name="viewport" content="width=device-width, initial-scale=1" />
         <title>{meta?.title || "app"}</title>
         <meta name="description" content={meta?.description} />
         <link rel="canonical" href={meta?.url || url} />

apps/front/src/styles/_breakpoints.scss

@@ -3,6 +3,8 @@
 $breakpoint-mobile: 320px;
 $breakpoint-mobile-horizontal: 500px;
 $breakpoint-tablet: 768px;
+$breakpoint-tablet-height: 950px;
 $breakpoint-laptop: 1024px;
+$breakpoint-bigLaptop-min: 1366px;
 $breakpoint-bigLaptop: 1440px;
 $breakpoint-desktop: 1680px;

apps/front/src/styles/_ratio.scss

@@ -1,6 +1,7 @@
 @use "./_viewport" as viewport;
 @use "./_breakpoints" as breakpoints;
 @use "./_functions" as fn;
+@use "./_utils" as utils;
 
 /// Set property calculated with VH & VW ratio
 /// @param {css property} $property
@@ -22,6 +23,20 @@
   }
 }
 
+@mixin mobileVH(
+  $property,
+  $n1,
+  $ratioVH: viewport.$viewport-reference-height,
+  $ratioVW: viewport.$viewport-reference-width
+) {
+  #{$property}: #{fn.ratioVH($n1, $ratioVH)};
+  @if $ratioVW > 0 {
+    @media (max-aspect-ratio: #{ #{$ratioVW} / #{$ratioVH+1} }) {
+      #{$property}: #{fn.ratioVW($n1, $ratioVW)};
+    }
+  }
+}
+
 /// Set property calculated with VW ratio
 /// @param {css property} $property
 /// @param {Number} $n1
@@ -87,19 +102,39 @@
   //Mobile
   @include propertyVW($property, $value1);
 
-  //Horizontal Desktop & Tablet
-  @include desktop($breakpoint) {
-    @include propertyVH($property, $value2, $ratioVW: 0);
+  // Landscape mobile
+  @include mobile-landscape {
+    @include propertyVH($property, $value2, viewport.$viewport-reference-width, 0);
+  }
+
+  // Portrait Tablet
+  @include tablet-portrait {
+    @include propertyVH(
+      $property,
+      $value2,
+      $ratioVW: viewport.$viewport-reference-tablet-width,
+      $ratioVH: viewport.$viewport-reference-tablet-height
+    );
+  }
+
+  // Landscape Tablet
+  @include tablet-landscape {
+    @include propertyVH(
+      $property,
+      $value2,
+      $ratioVW: viewport.$viewport-reference-tablet-width,
+      $ratioVH: viewport.$viewport-reference-tablet-height
+    );
   }
 
   //Portrait Desktop & Tablet
   @include desktop-portrait {
     @include propertyVW($property, $value2, viewport.$viewport-reference-tablet-width);
   }
 
-  //Horizontal mobile
-  @include mobile-landscape {
-    @include propertyVH($property, $value2, viewport.$viewport-reference-width, 0);
+  //Horizontal Desktop & Tablet
+  @include desktop($breakpoint) {
+    @include propertyVH($property, $value2, $ratioVW: 0);
   }
 
   @if $cap {
@@ -136,15 +171,31 @@
 /// Desktop & Tablet portrait media query
 /// @param {string} [$breakpoint=breakpoints.$breakpoint-tablet] - Le point de rupture pour les médias queries (par défaut égal à breakpoints.$breakpoint-tablet).
 @mixin desktop-portrait($breakpoint: breakpoints.$breakpoint-tablet) {
-  @media (min-width: $breakpoint) and (orientation: portrait) {
+  @media (min-width: $breakpoint) and (min-height: breakpoints.$breakpoint-bigLaptop) and (orientation: portrait) {
     @content;
   }
 }
 
 /// Mobile landscape media query.
+/// @param {string} [$breakpoint=breakpoints.$breakpoint-tablet] - Le point de rupture pour les médias queries (par défaut égal à breakpoints.$breakpoint-laptop).
+@mixin mobile-landscape($breakpoint: breakpoints.$breakpoint-tablet) {
+  @media (max-width: #{$breakpoint + 1}) and (orientation: landscape) {
+    @content;
+  }
+}
+
+/// Tablet landscape media query.
 /// @param {string} [$breakpoint=breakpoints.$breakpoint-laptop] - Le point de rupture pour les médias queries (par défaut égal à breakpoints.$breakpoint-laptop).
-@mixin mobile-landscape($breakpoint: breakpoints.$breakpoint-laptop) {
-  @media (max-width: #{$breakpoint - 1}) and (orientation: landscape) {
+@mixin tablet-landscape($breakpoint: breakpoints.$breakpoint-laptop) {
+  @media (max-width: #{breakpoints.$breakpoint-bigLaptop-min + 1}) and (min-width: #{$breakpoint}) and (orientation: landscape) {
+    @content;
+  }
+}
+
+/// Tablet portrait media query.
+/// @param {string} [$breakpoint=breakpoints.$breakpoints-tablet-height] - Le point de rupture pour les médias queries (par défaut égal à breakpoints.$breakpoint-laptop).
+@mixin tablet-portrait($breakpoint: breakpoints.$breakpoint-tablet-height) {
+  @media (min-height: #{$breakpoint}) and (orientation: portrait) {
     @content;
   }
 }

apps/front/src/styles/breakpoints-inline.scss

@@ -4,7 +4,9 @@
   --breakpoint-mobile: #{$breakpoint-mobile};
   --breakpoint-mobile-horizontal: #{$breakpoint-mobile-horizontal};
   --breakpoint-tablet: #{$breakpoint-tablet};
+  --breakpoint-tablet-height: #{$breakpoint-tablet-height};
   --breakpoint-laptop: #{$breakpoint-laptop};
+  --breakpoint-bigLaptop-min: #{$breakpoint-bigLaptop-min};
   --breakpoint-bigLaptop: #{$breakpoint-bigLaptop};
   --breakpoint-desktop: #{$breakpoint-desktop};
 }

cli/tasks/scaffold-component/templates/react/page.tsx.template

@@ -35,7 +35,7 @@ const %%upperComponentName%% = forwardRef((props: IProps, handleRef: ForwardedRe
 
   return (
     <div className={css.root} ref={rootRef}>
-      {componentName}
+      <h1>{componentName}</h1>
     </div>
   );
 });