astro/packages/integrations/image/components/Picture.astro
Jan Müller 72c760e9b8
feat(image): throw if alt text is missing (#4511)
* feat(image): throw if no `alt` is provided

* chore: add changeset

* docs(image): update README

* updated alt text stuff throughout

* fixing with-mdx test suite

* warn for missing alt text, will throw an error in a future release

* final README tweaks

Co-authored-by: Tony Sullivan <tony.f.sullivan@outlook.com>
Co-authored-by: Sarah Rainsberger <sarah@rainsberger.ca>
2022-09-01 21:24:07 +00:00

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---
import { getPicture } from '../dist/index.js';
import { warnForMissingAlt } from './index.js';
import type { ImgHTMLAttributes, HTMLAttributes } from './index.js';
import type { ImageMetadata, OutputFormat, TransformOptions } from '../dist/index.js';
interface LocalImageProps
extends Omit<HTMLAttributes, 'src' | 'width' | 'height'>,
Omit<TransformOptions, 'src'>,
Pick<astroHTML.JSX.ImgHTMLAttributes, 'loading' | 'decoding'> {
src: ImageMetadata | Promise<{ default: ImageMetadata }>;
/** Defines an alternative text description of the image. Set to an empty string (alt="") if the image is not a key part of the content (it's decoration or a tracking pixel). */
alt: string;
sizes: HTMLImageElement['sizes'];
widths: number[];
formats?: OutputFormat[];
}
interface RemoteImageProps
extends Omit<HTMLAttributes, 'src' | 'width' | 'height'>,
TransformOptions,
Pick<ImgHTMLAttributes, 'loading' | 'decoding'> {
src: string;
/** Defines an alternative text description of the image. Set to an empty string (alt="") if the image is not a key part of the content (it's decoration or a tracking pixel). */
alt: string;
sizes: HTMLImageElement['sizes'];
widths: number[];
aspectRatio: TransformOptions['aspectRatio'];
formats?: OutputFormat[];
}
export type Props = LocalImageProps | RemoteImageProps;
const {
src,
alt,
sizes,
widths,
aspectRatio,
formats = ['avif', 'webp'],
loading = 'lazy',
decoding = 'async',
...attrs
} = Astro.props as Props;
if (alt === undefined || alt === null) {
warnForMissingAlt();
}
const { image, sources } = await getPicture({ src, widths, formats, aspectRatio });
---
<picture {...attrs}>
{sources.map((attrs) => <source {...attrs} {sizes} />)}
<img {...image} {loading} {decoding} {alt} />
</picture>
<style>
img {
content-visibility: auto;
}
</style>