rsnext/packages/next/client/image.tsx
Steven 9f0024a5ee
Change experimental layout=raw to use native img lazy loading (#36985)
This PR changes the experimental `layout=raw` images to use the native lazy loading behavior (as opposed to the IntersectionObserver).

This will (eventually) lead to smaller client bundles and faster image loading since there is no JS needed to load the image.

However, we'll lose the `lazyRoot` and `lazyBoundary` behavior since those are specific to the IntersectionObserver implementation.
2022-05-18 21:05:15 +00:00

1121 lines
33 KiB
TypeScript

import React, {
useRef,
useEffect,
useCallback,
useContext,
useMemo,
useState,
} from 'react'
import Head from '../shared/lib/head'
import {
ImageConfigComplete,
imageConfigDefault,
LoaderValue,
VALID_LOADERS,
} from '../shared/lib/image-config'
import { useIntersection } from './use-intersection'
import { ImageConfigContext } from '../shared/lib/image-config-context'
import { warnOnce } from '../shared/lib/utils'
import { normalizePathTrailingSlash } from './normalize-trailing-slash'
const { experimentalLayoutRaw = false, experimentalRemotePatterns = [] } =
(process.env.__NEXT_IMAGE_OPTS as any) || {}
const configEnv = process.env.__NEXT_IMAGE_OPTS as any as ImageConfigComplete
const loadedImageURLs = new Set<string>()
const allImgs = new Map<
string,
{ src: string; priority: boolean; placeholder: string }
>()
let perfObserver: PerformanceObserver | undefined
const emptyDataURL =
'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7'
if (typeof window === 'undefined') {
;(global as any).__NEXT_IMAGE_IMPORTED = true
}
const VALID_LOADING_VALUES = ['lazy', 'eager', undefined] as const
type LoadingValue = typeof VALID_LOADING_VALUES[number]
type ImageConfig = ImageConfigComplete & { allSizes: number[] }
export type ImageLoader = (resolverProps: ImageLoaderProps) => string
export type ImageLoaderProps = {
src: string
width: number
quality?: number
}
// Do not export - this is an internal type only
// because `next.config.js` is only meant for the
// built-in loaders, not for a custom loader() prop.
type ImageLoaderWithConfig = (
resolverProps: ImageLoaderPropsWithConfig
) => string
type ImageLoaderPropsWithConfig = ImageLoaderProps & {
config: Readonly<ImageConfig>
}
const loaders = new Map<
LoaderValue,
(props: ImageLoaderPropsWithConfig) => string
>([
['default', defaultLoader],
['imgix', imgixLoader],
['cloudinary', cloudinaryLoader],
['akamai', akamaiLoader],
['custom', customLoader],
])
const VALID_LAYOUT_VALUES = [
'fill',
'fixed',
'intrinsic',
'responsive',
'raw',
undefined,
] as const
type LayoutValue = typeof VALID_LAYOUT_VALUES[number]
type PlaceholderValue = 'blur' | 'empty'
type OnLoadingComplete = (result: {
naturalWidth: number
naturalHeight: number
}) => void
type ImgElementStyle = NonNullable<JSX.IntrinsicElements['img']['style']>
type ImgElementWithDataProp = HTMLImageElement & {
'data-loaded-src': string | undefined
}
export interface StaticImageData {
src: string
height: number
width: number
blurDataURL?: string
}
interface StaticRequire {
default: StaticImageData
}
type StaticImport = StaticRequire | StaticImageData
function isStaticRequire(
src: StaticRequire | StaticImageData
): src is StaticRequire {
return (src as StaticRequire).default !== undefined
}
function isStaticImageData(
src: StaticRequire | StaticImageData
): src is StaticImageData {
return (src as StaticImageData).src !== undefined
}
function isStaticImport(src: string | StaticImport): src is StaticImport {
return (
typeof src === 'object' &&
(isStaticRequire(src as StaticImport) ||
isStaticImageData(src as StaticImport))
)
}
export type ImageProps = Omit<
JSX.IntrinsicElements['img'],
'src' | 'srcSet' | 'ref' | 'width' | 'height' | 'loading'
> & {
src: string | StaticImport
width?: number | string
height?: number | string
layout?: LayoutValue
loader?: ImageLoader
quality?: number | string
priority?: boolean
loading?: LoadingValue
lazyRoot?: React.RefObject<HTMLElement> | null
lazyBoundary?: string
placeholder?: PlaceholderValue
blurDataURL?: string
unoptimized?: boolean
objectFit?: ImgElementStyle['objectFit']
objectPosition?: ImgElementStyle['objectPosition']
onLoadingComplete?: OnLoadingComplete
}
type ImageElementProps = Omit<ImageProps, 'src' | 'loader'> & {
srcString: string
imgAttributes: GenImgAttrsResult
heightInt: number | undefined
widthInt: number | undefined
qualityInt: number | undefined
layout: LayoutValue
imgStyle: ImgElementStyle
blurStyle: ImgElementStyle
isLazy: boolean
loading: LoadingValue
config: ImageConfig
unoptimized: boolean
loader: ImageLoaderWithConfig
placeholder: PlaceholderValue
onLoadingCompleteRef: React.MutableRefObject<OnLoadingComplete | undefined>
setBlurComplete: (b: boolean) => void
setIntersection: (img: HTMLImageElement | null) => void
isVisible: boolean
}
function getWidths(
{ deviceSizes, allSizes }: ImageConfig,
width: number | undefined,
layout: LayoutValue,
sizes: string | undefined
): { widths: number[]; kind: 'w' | 'x' } {
if (
sizes &&
(layout === 'fill' || layout === 'responsive' || layout === 'raw')
) {
// Find all the "vw" percent sizes used in the sizes prop
const viewportWidthRe = /(^|\s)(1?\d?\d)vw/g
const percentSizes = []
for (let match; (match = viewportWidthRe.exec(sizes)); match) {
percentSizes.push(parseInt(match[2]))
}
if (percentSizes.length) {
const smallestRatio = Math.min(...percentSizes) * 0.01
return {
widths: allSizes.filter((s) => s >= deviceSizes[0] * smallestRatio),
kind: 'w',
}
}
return { widths: allSizes, kind: 'w' }
}
if (
typeof width !== 'number' ||
layout === 'fill' ||
layout === 'responsive'
) {
return { widths: deviceSizes, kind: 'w' }
}
const widths = [
...new Set(
// > This means that most OLED screens that say they are 3x resolution,
// > are actually 3x in the green color, but only 1.5x in the red and
// > blue colors. Showing a 3x resolution image in the app vs a 2x
// > resolution image will be visually the same, though the 3x image
// > takes significantly more data. Even true 3x resolution screens are
// > wasteful as the human eye cannot see that level of detail without
// > something like a magnifying glass.
// https://blog.twitter.com/engineering/en_us/topics/infrastructure/2019/capping-image-fidelity-on-ultra-high-resolution-devices.html
[width, width * 2 /*, width * 3*/].map(
(w) => allSizes.find((p) => p >= w) || allSizes[allSizes.length - 1]
)
),
]
return { widths, kind: 'x' }
}
type GenImgAttrsData = {
config: ImageConfig
src: string
unoptimized: boolean
layout: LayoutValue
loader: ImageLoaderWithConfig
width?: number
quality?: number
sizes?: string
}
type GenImgAttrsResult = {
src: string
srcSet: string | undefined
sizes: string | undefined
}
function generateImgAttrs({
config,
src,
unoptimized,
layout,
width,
quality,
sizes,
loader,
}: GenImgAttrsData): GenImgAttrsResult {
if (unoptimized) {
return { src, srcSet: undefined, sizes: undefined }
}
const { widths, kind } = getWidths(config, width, layout, sizes)
const last = widths.length - 1
return {
sizes: !sizes && kind === 'w' ? '100vw' : sizes,
srcSet: widths
.map(
(w, i) =>
`${loader({ config, src, quality, width: w })} ${
kind === 'w' ? w : i + 1
}${kind}`
)
.join(', '),
// It's intended to keep `src` the last attribute because React updates
// attributes in order. If we keep `src` the first one, Safari will
// immediately start to fetch `src`, before `sizes` and `srcSet` are even
// updated by React. That causes multiple unnecessary requests if `srcSet`
// and `sizes` are defined.
// This bug cannot be reproduced in Chrome or Firefox.
src: loader({ config, src, quality, width: widths[last] }),
}
}
function getInt(x: unknown): number | undefined {
if (typeof x === 'number') {
return x
}
if (typeof x === 'string') {
return parseInt(x, 10)
}
return undefined
}
function defaultImageLoader(loaderProps: ImageLoaderPropsWithConfig) {
const loaderKey = loaderProps.config?.loader || 'default'
const load = loaders.get(loaderKey)
if (load) {
return load(loaderProps)
}
throw new Error(
`Unknown "loader" found in "next.config.js". Expected: ${VALID_LOADERS.join(
', '
)}. Received: ${loaderKey}`
)
}
// See https://stackoverflow.com/q/39777833/266535 for why we use this ref
// handler instead of the img's onLoad attribute.
function handleLoading(
img: ImgElementWithDataProp,
src: string,
layout: LayoutValue,
placeholder: PlaceholderValue,
onLoadingCompleteRef: React.MutableRefObject<OnLoadingComplete | undefined>,
setBlurComplete: (b: boolean) => void
) {
if (!img || img.src === emptyDataURL || img['data-loaded-src'] === src) {
return
}
img['data-loaded-src'] = src
const p = 'decode' in img ? img.decode() : Promise.resolve()
p.catch(() => {}).then(() => {
if (!img.parentNode) {
// Exit early in case of race condition:
// - onload() is called
// - decode() is called but incomplete
// - unmount is called
// - decode() completes
return
}
loadedImageURLs.add(src)
if (placeholder === 'blur') {
setBlurComplete(true)
}
if (onLoadingCompleteRef?.current) {
const { naturalWidth, naturalHeight } = img
// Pass back read-only primitive values but not the
// underlying DOM element because it could be misused.
onLoadingCompleteRef.current({ naturalWidth, naturalHeight })
}
if (process.env.NODE_ENV !== 'production') {
if (layout === 'raw') {
const heightModified =
img.height.toString() !== img.getAttribute('height')
const widthModified = img.width.toString() !== img.getAttribute('width')
if (
(heightModified && !widthModified) ||
(!heightModified && widthModified)
) {
warnOnce(
`Image with src "${src}" has either width or height modified, but not the other. If you use CSS to change the size of your image, also include the styles 'width: "auto"' or 'height: "auto"' to maintain the aspect ratio.`
)
}
}
if (img.parentElement?.parentElement) {
const parent = getComputedStyle(img.parentElement.parentElement)
if (!parent.position) {
// The parent has not been rendered to the dom yet and therefore it has no position. Skip the warnings for such cases.
} else if (layout === 'responsive' && parent.display === 'flex') {
warnOnce(
`Image with src "${src}" may not render properly as a child of a flex container. Consider wrapping the image with a div to configure the width.`
)
} else if (
layout === 'fill' &&
parent.position !== 'relative' &&
parent.position !== 'fixed' &&
parent.position !== 'absolute'
) {
warnOnce(
`Image with src "${src}" may not render properly with a parent using position:"${parent.position}". Consider changing the parent style to position:"relative" with a width and height.`
)
}
}
}
})
}
export default function Image({
src,
sizes,
unoptimized = false,
priority = false,
loading,
lazyRoot = null,
lazyBoundary,
className,
quality,
width,
height,
style,
objectFit,
objectPosition,
onLoadingComplete,
placeholder = 'empty',
blurDataURL,
...all
}: ImageProps) {
const configContext = useContext(ImageConfigContext)
const config: ImageConfig = useMemo(() => {
const c = configEnv || configContext || imageConfigDefault
const allSizes = [...c.deviceSizes, ...c.imageSizes].sort((a, b) => a - b)
const deviceSizes = c.deviceSizes.sort((a, b) => a - b)
return { ...c, allSizes, deviceSizes }
}, [configContext])
let rest: Partial<ImageProps> = all
let layout: NonNullable<LayoutValue> = sizes ? 'responsive' : 'intrinsic'
if ('layout' in rest) {
// Override default layout if the user specified one:
if (rest.layout) layout = rest.layout
// Remove property so it's not spread on <img>:
delete rest.layout
}
let loader: ImageLoaderWithConfig = defaultImageLoader
if ('loader' in rest) {
if (rest.loader) {
const customImageLoader = rest.loader
loader = (obj) => {
const { config: _, ...opts } = obj
// The config object is internal only so we must
// not pass it to the user-defined loader()
return customImageLoader(opts)
}
}
// Remove property so it's not spread on <img>
delete rest.loader
}
let staticSrc = ''
if (isStaticImport(src)) {
const staticImageData = isStaticRequire(src) ? src.default : src
if (!staticImageData.src) {
throw new Error(
`An object should only be passed to the image component src parameter if it comes from a static image import. It must include src. Received ${JSON.stringify(
staticImageData
)}`
)
}
blurDataURL = blurDataURL || staticImageData.blurDataURL
staticSrc = staticImageData.src
if (!layout || layout !== 'fill') {
height = height || staticImageData.height
width = width || staticImageData.width
if (!staticImageData.height || !staticImageData.width) {
throw new Error(
`An object should only be passed to the image component src parameter if it comes from a static image import. It must include height and width. Received ${JSON.stringify(
staticImageData
)}`
)
}
}
}
src = typeof src === 'string' ? src : staticSrc
const widthInt = getInt(width)
const heightInt = getInt(height)
const qualityInt = getInt(quality)
let isLazy =
!priority && (loading === 'lazy' || typeof loading === 'undefined')
if (src.startsWith('data:') || src.startsWith('blob:')) {
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs
unoptimized = true
isLazy = false
}
if (typeof window !== 'undefined' && loadedImageURLs.has(src)) {
isLazy = false
}
const [blurComplete, setBlurComplete] = useState(false)
const [setIntersection, isIntersected, resetIntersected] =
useIntersection<HTMLImageElement>({
rootRef: lazyRoot,
rootMargin: lazyBoundary || '200px',
disabled: !isLazy,
})
const isVisible = !isLazy || isIntersected || layout === 'raw'
const wrapperStyle: JSX.IntrinsicElements['span']['style'] = {
boxSizing: 'border-box',
display: 'block',
overflow: 'hidden',
width: 'initial',
height: 'initial',
background: 'none',
opacity: 1,
border: 0,
margin: 0,
padding: 0,
}
const sizerStyle: JSX.IntrinsicElements['span']['style'] = {
boxSizing: 'border-box',
display: 'block',
width: 'initial',
height: 'initial',
background: 'none',
opacity: 1,
border: 0,
margin: 0,
padding: 0,
}
let hasSizer = false
let sizerSvgUrl: string | undefined
const layoutStyle: ImgElementStyle = {
position: 'absolute',
top: 0,
left: 0,
bottom: 0,
right: 0,
boxSizing: 'border-box',
padding: 0,
border: 'none',
margin: 'auto',
display: 'block',
width: 0,
height: 0,
minWidth: '100%',
maxWidth: '100%',
minHeight: '100%',
maxHeight: '100%',
objectFit,
objectPosition,
}
if (process.env.NODE_ENV !== 'production' && layout !== 'raw' && style) {
}
if (process.env.NODE_ENV !== 'production') {
if (!src) {
throw new Error(
`Image is missing required "src" property. Make sure you pass "src" in props to the \`next/image\` component. Received: ${JSON.stringify(
{ width, height, quality }
)}`
)
}
if (!VALID_LAYOUT_VALUES.includes(layout)) {
throw new Error(
`Image with src "${src}" has invalid "layout" property. Provided "${layout}" should be one of ${VALID_LAYOUT_VALUES.map(
String
).join(',')}.`
)
}
if (layout === 'raw' && !experimentalLayoutRaw) {
throw new Error(
`The "raw" layout is currently experimental and may be subject to breaking changes. To use layout="raw", include \`experimental: { images: { layoutRaw: true } }\` in your next.config.js file.`
)
}
if (
(typeof widthInt !== 'undefined' && isNaN(widthInt)) ||
(typeof heightInt !== 'undefined' && isNaN(heightInt))
) {
throw new Error(
`Image with src "${src}" has invalid "width" or "height" property. These should be numeric values.`
)
}
if (layout === 'fill' && (width || height)) {
warnOnce(
`Image with src "${src}" and "layout='fill'" has unused properties assigned. Please remove "width" and "height".`
)
}
if (!VALID_LOADING_VALUES.includes(loading)) {
throw new Error(
`Image with src "${src}" has invalid "loading" property. Provided "${loading}" should be one of ${VALID_LOADING_VALUES.map(
String
).join(',')}.`
)
}
if (priority && loading === 'lazy') {
throw new Error(
`Image with src "${src}" has both "priority" and "loading='lazy'" properties. Only one should be used.`
)
}
if (layout === 'raw') {
if (objectFit) {
throw new Error(
`Image with src "${src}" has "layout='raw'" and "objectFit='${objectFit}'". For raw images, these and other styles should be specified using the "style" attribute.`
)
}
if (objectPosition) {
throw new Error(
`Image with src "${src}" has "layout='raw'" and "objectPosition='${objectPosition}'". For raw images, these and other styles should be specified using the "style" attribute.`
)
}
if (lazyRoot) {
throw new Error(
`Image with src "${src}" has "layout='raw'" and "lazyRoot='${lazyRoot}'". For raw images, native lazy loading is used so "lazyRoot" cannot be used.`
)
}
if (lazyBoundary) {
throw new Error(
`Image with src "${src}" has "layout='raw'" and "lazyBoundary='${lazyBoundary}'". For raw images, native lazy loading is used so "lazyBoundary" cannot be used.`
)
}
}
if (
sizes &&
layout !== 'fill' &&
layout !== 'responsive' &&
layout !== 'raw'
) {
warnOnce(
`Image with src "${src}" has "sizes" property but it will be ignored. Only use "sizes" with "layout='fill'", "layout='responsive'", or "layout='raw'`
)
}
if (placeholder === 'blur') {
if (layout !== 'fill' && (widthInt || 0) * (heightInt || 0) < 1600) {
warnOnce(
`Image with src "${src}" is smaller than 40x40. Consider removing the "placeholder='blur'" property to improve performance.`
)
}
if (!blurDataURL) {
const VALID_BLUR_EXT = ['jpeg', 'png', 'webp', 'avif'] // should match next-image-loader
throw new Error(
`Image with src "${src}" has "placeholder='blur'" property but is missing the "blurDataURL" property.
Possible solutions:
- Add a "blurDataURL" property, the contents should be a small Data URL to represent the image
- Change the "src" property to a static import with one of the supported file types: ${VALID_BLUR_EXT.join(
','
)}
- Remove the "placeholder" property, effectively no blur effect
Read more: https://nextjs.org/docs/messages/placeholder-blur-data-url`
)
}
}
if ('ref' in rest) {
warnOnce(
`Image with src "${src}" is using unsupported "ref" property. Consider using the "onLoadingComplete" property instead.`
)
}
if (!unoptimized && loader !== defaultImageLoader) {
const urlStr = loader({
config,
src,
width: widthInt || 400,
quality: qualityInt || 75,
})
let url: URL | undefined
try {
url = new URL(urlStr)
} catch (err) {}
if (urlStr === src || (url && url.pathname === src && !url.search)) {
warnOnce(
`Image with src "${src}" has a "loader" property that does not implement width. Please implement it or use the "unoptimized" property instead.` +
`\nRead more: https://nextjs.org/docs/messages/next-image-missing-loader-width`
)
}
}
if (style && layout !== 'raw') {
let overwrittenStyles = Object.keys(style).filter(
(key) => key in layoutStyle
)
if (overwrittenStyles.length) {
warnOnce(
`Image with src ${src} is assigned the following styles, which are overwritten by automatically-generated styles: ${overwrittenStyles.join(
', '
)}`
)
}
}
if (
typeof window !== 'undefined' &&
!perfObserver &&
window.PerformanceObserver
) {
perfObserver = new PerformanceObserver((entryList) => {
for (const entry of entryList.getEntries()) {
// @ts-ignore - missing "LargestContentfulPaint" class with "element" prop
const imgSrc = entry?.element?.src || ''
const lcpImage = allImgs.get(imgSrc)
if (
lcpImage &&
!lcpImage.priority &&
lcpImage.placeholder !== 'blur' &&
!lcpImage.src.startsWith('data:') &&
!lcpImage.src.startsWith('blob:')
) {
// https://web.dev/lcp/#measure-lcp-in-javascript
warnOnce(
`Image with src "${lcpImage.src}" was detected as the Largest Contentful Paint (LCP). Please add the "priority" property if this image is above the fold.` +
`\nRead more: https://nextjs.org/docs/api-reference/next/image#priority`
)
}
}
})
try {
perfObserver.observe({
type: 'largest-contentful-paint',
buffered: true,
})
} catch (err) {
// Log error but don't crash the app
console.error(err)
}
}
}
const imgStyle = Object.assign({}, style, layout === 'raw' ? {} : layoutStyle)
const blurStyle =
placeholder === 'blur' && !blurComplete
? {
filter: 'blur(20px)',
backgroundSize: objectFit || 'cover',
backgroundImage: `url("${blurDataURL}")`,
backgroundPosition: objectPosition || '0% 0%',
}
: {}
if (layout === 'fill') {
// <Image src="i.png" layout="fill" />
wrapperStyle.display = 'block'
wrapperStyle.position = 'absolute'
wrapperStyle.top = 0
wrapperStyle.left = 0
wrapperStyle.bottom = 0
wrapperStyle.right = 0
} else if (
typeof widthInt !== 'undefined' &&
typeof heightInt !== 'undefined'
) {
// <Image src="i.png" width="100" height="100" />
const quotient = heightInt / widthInt
const paddingTop = isNaN(quotient) ? '100%' : `${quotient * 100}%`
if (layout === 'responsive') {
// <Image src="i.png" width="100" height="100" layout="responsive" />
wrapperStyle.display = 'block'
wrapperStyle.position = 'relative'
hasSizer = true
sizerStyle.paddingTop = paddingTop
} else if (layout === 'intrinsic') {
// <Image src="i.png" width="100" height="100" layout="intrinsic" />
wrapperStyle.display = 'inline-block'
wrapperStyle.position = 'relative'
wrapperStyle.maxWidth = '100%'
hasSizer = true
sizerStyle.maxWidth = '100%'
sizerSvgUrl = `data:image/svg+xml,%3csvg%20xmlns=%27http://www.w3.org/2000/svg%27%20version=%271.1%27%20width=%27${widthInt}%27%20height=%27${heightInt}%27/%3e`
} else if (layout === 'fixed') {
// <Image src="i.png" width="100" height="100" layout="fixed" />
wrapperStyle.display = 'inline-block'
wrapperStyle.position = 'relative'
wrapperStyle.width = widthInt
wrapperStyle.height = heightInt
}
} else {
// <Image src="i.png" />
if (process.env.NODE_ENV !== 'production') {
throw new Error(
`Image with src "${src}" must use "width" and "height" properties or "layout='fill'" property.`
)
}
}
let imgAttributes: GenImgAttrsResult = {
src: emptyDataURL,
srcSet: undefined,
sizes: undefined,
}
if (isVisible) {
imgAttributes = generateImgAttrs({
config,
src,
unoptimized,
layout,
width: widthInt,
quality: qualityInt,
sizes,
loader,
})
}
let srcString: string = src
if (process.env.NODE_ENV !== 'production') {
if (typeof window !== 'undefined') {
let fullUrl: URL
try {
fullUrl = new URL(imgAttributes.src)
} catch (e) {
fullUrl = new URL(imgAttributes.src, window.location.href)
}
allImgs.set(fullUrl.href, { src, priority, placeholder })
}
}
let imageSrcSetPropName = 'imagesrcset'
let imageSizesPropName = 'imagesizes'
if (process.env.__NEXT_REACT_ROOT) {
imageSrcSetPropName = 'imageSrcSet'
imageSizesPropName = 'imageSizes'
}
const linkProps = {
// Note: imagesrcset and imagesizes are not in the link element type with react 17.
[imageSrcSetPropName]: imgAttributes.srcSet,
[imageSizesPropName]: imgAttributes.sizes,
}
const useLayoutEffect =
typeof window === 'undefined' ? React.useEffect : React.useLayoutEffect
const onLoadingCompleteRef = useRef(onLoadingComplete)
const previousImageSrc = useRef<string | StaticImport>(src)
useEffect(() => {
onLoadingCompleteRef.current = onLoadingComplete
}, [onLoadingComplete])
useLayoutEffect(() => {
if (previousImageSrc.current !== src) {
resetIntersected()
previousImageSrc.current = src
}
}, [resetIntersected, src])
const imgElementArgs = {
isLazy,
imgAttributes,
heightInt,
widthInt,
qualityInt,
layout,
className,
imgStyle,
blurStyle,
loading,
config,
unoptimized,
placeholder,
loader,
srcString,
onLoadingCompleteRef,
setBlurComplete,
setIntersection,
isVisible,
...rest,
}
return (
<>
{layout === 'raw' ? (
<ImageElement {...imgElementArgs} />
) : (
<span style={wrapperStyle}>
{hasSizer ? (
<span style={sizerStyle}>
{sizerSvgUrl ? (
<img
style={{
display: 'block',
maxWidth: '100%',
width: 'initial',
height: 'initial',
background: 'none',
opacity: 1,
border: 0,
margin: 0,
padding: 0,
}}
alt=""
aria-hidden={true}
src={sizerSvgUrl}
/>
) : null}
</span>
) : null}
<ImageElement {...imgElementArgs} />
</span>
)}
{priority ? (
// Note how we omit the `href` attribute, as it would only be relevant
// for browsers that do not support `imagesrcset`, and in those cases
// it would likely cause the incorrect image to be preloaded.
//
// https://html.spec.whatwg.org/multipage/semantics.html#attr-link-imagesrcset
<Head>
<link
key={
'__nimg-' +
imgAttributes.src +
imgAttributes.srcSet +
imgAttributes.sizes
}
rel="preload"
as="image"
href={imgAttributes.srcSet ? undefined : imgAttributes.src}
{...linkProps}
/>
</Head>
) : null}
</>
)
}
const ImageElement = ({
imgAttributes,
heightInt,
widthInt,
qualityInt,
layout,
className,
imgStyle,
blurStyle,
isLazy,
placeholder,
loading = 'lazy',
srcString,
config,
unoptimized,
loader,
onLoadingCompleteRef,
setBlurComplete,
setIntersection,
onLoad,
onError,
isVisible,
...rest
}: ImageElementProps) => {
return (
<>
<img
{...rest}
{...imgAttributes}
{...(layout === 'raw' ? { height: heightInt, width: widthInt } : {})}
decoding="async"
data-nimg={layout}
className={className}
// @ts-ignore - TODO: upgrade to `@types/react@17`
loading={layout === 'raw' ? loading : undefined}
style={{ ...imgStyle, ...blurStyle }}
ref={useCallback(
(img: ImgElementWithDataProp) => {
setIntersection(img)
if (img?.complete) {
handleLoading(
img,
srcString,
layout,
placeholder,
onLoadingCompleteRef,
setBlurComplete
)
}
},
[
setIntersection,
srcString,
layout,
placeholder,
onLoadingCompleteRef,
setBlurComplete,
]
)}
onLoad={(event) => {
const img = event.currentTarget as ImgElementWithDataProp
handleLoading(
img,
srcString,
layout,
placeholder,
onLoadingCompleteRef,
setBlurComplete
)
if (onLoad) {
onLoad(event)
}
}}
onError={(event) => {
if (placeholder === 'blur') {
// If the real image fails to load, this will still remove the placeholder.
setBlurComplete(true)
}
if (onError) {
onError(event)
}
}}
/>
{(isLazy || placeholder === 'blur') && (
<noscript>
<img
{...rest}
{...generateImgAttrs({
config,
src: srcString,
unoptimized,
layout,
width: widthInt,
quality: qualityInt,
sizes: imgAttributes.sizes,
loader,
})}
{...(layout === 'raw'
? { height: heightInt, width: widthInt }
: {})}
decoding="async"
data-nimg={layout}
style={imgStyle}
className={className}
// @ts-ignore - TODO: upgrade to `@types/react@17`
loading={loading}
/>
</noscript>
)}
</>
)
}
function normalizeSrc(src: string): string {
return src[0] === '/' ? src.slice(1) : src
}
function imgixLoader({
config,
src,
width,
quality,
}: ImageLoaderPropsWithConfig): string {
// Demo: https://static.imgix.net/daisy.png?auto=format&fit=max&w=300
const url = new URL(`${config.path}${normalizeSrc(src)}`)
const params = url.searchParams
params.set('auto', params.get('auto') || 'format')
params.set('fit', params.get('fit') || 'max')
params.set('w', params.get('w') || width.toString())
if (quality) {
params.set('q', quality.toString())
}
return url.href
}
function akamaiLoader({
config,
src,
width,
}: ImageLoaderPropsWithConfig): string {
return `${config.path}${normalizeSrc(src)}?imwidth=${width}`
}
function cloudinaryLoader({
config,
src,
width,
quality,
}: ImageLoaderPropsWithConfig): string {
// Demo: https://res.cloudinary.com/demo/image/upload/w_300,c_limit,q_auto/turtles.jpg
const params = ['f_auto', 'c_limit', 'w_' + width, 'q_' + (quality || 'auto')]
const paramsString = params.join(',') + '/'
return `${config.path}${paramsString}${normalizeSrc(src)}`
}
function customLoader({ src }: ImageLoaderProps): string {
throw new Error(
`Image with src "${src}" is missing "loader" prop.` +
`\nRead more: https://nextjs.org/docs/messages/next-image-missing-loader`
)
}
function defaultLoader({
config,
src,
width,
quality,
}: ImageLoaderPropsWithConfig): string {
if (process.env.NODE_ENV !== 'production') {
const missingValues = []
// these should always be provided but make sure they are
if (!src) missingValues.push('src')
if (!width) missingValues.push('width')
if (missingValues.length > 0) {
throw new Error(
`Next Image Optimization requires ${missingValues.join(
', '
)} to be provided. Make sure you pass them as props to the \`next/image\` component. Received: ${JSON.stringify(
{ src, width, quality }
)}`
)
}
if (src.startsWith('//')) {
throw new Error(
`Failed to parse src "${src}" on \`next/image\`, protocol-relative URL (//) must be changed to an absolute URL (http:// or https://)`
)
}
if (
!src.startsWith('/') &&
(config.domains || experimentalRemotePatterns)
) {
let parsedSrc: URL
try {
parsedSrc = new URL(src)
} catch (err) {
console.error(err)
throw new Error(
`Failed to parse src "${src}" on \`next/image\`, if using relative image it must start with a leading slash "/" or be an absolute URL (http:// or https://)`
)
}
if (process.env.NODE_ENV !== 'test') {
// We use dynamic require because this should only error in development
const { hasMatch } = require('../shared/lib/match-remote-pattern')
if (!hasMatch(config.domains, experimentalRemotePatterns, parsedSrc)) {
throw new Error(
`Invalid src prop (${src}) on \`next/image\`, hostname "${parsedSrc.hostname}" is not configured under images in your \`next.config.js\`\n` +
`See more info: https://nextjs.org/docs/messages/next-image-unconfigured-host`
)
}
}
}
}
if (src.endsWith('.svg') && !config.dangerouslyAllowSVG) {
// Special case to make svg serve as-is to avoid proxying
// through the built-in Image Optimization API.
return src
}
return `${normalizePathTrailingSlash(config.path)}?url=${encodeURIComponent(
src
)}&w=${width}&q=${quality || 75}`
}