@benjc/rehype-semantic-images
v0.1.0
Published
This unified ecosystem plugin enriches HTML images with semantic elements and customizable features, improving accessibility and performance through options like lazy loading and dynamic source modification.
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rehype-semantic-images
This plugin enhances images in HTML documents processed by rehype in the unified ecosystem. It adds semantic elements such as figure, figcaption, and customizable container elements, and supports lazy loading options, custom class names, and IDs. It enables dynamic source set and URL building, which allows developers to improve accessibility, SEO, and performance of web pages. With fine-grained control over image presentation and loading behavior, this plugin provides developers with greater flexibility and customization options.
Install
npm i -D @benjc/rehype-semantic-images
Usage
import rehypeSemanticImages from "@benjc/rehype-semantic-images";
import rehype from "rehype";
import rehypeParse from "rehype-parse";
import { unified } from "unified";
unified()
.use(rehypeParse, { fragment: true })
.use(rehypeSemanticImages)
.process(`<img src="image.jpg" alt="My alt text" />`);
// Or with options:
unified()
.use(rehypeParse, { fragment: true })
.use(rehypeSemanticImages, {
urlBuilder: (src) => `https://my-cdn.com/${src}`,
})
.process(`<img src="image.jpg" alt="My alt text" />`);
Input
<img src="image.jpg" alt="My alt text" />
Output
<figure class="rsi-figure">
<div class="rsi-container">
<img class="rsi-image" alt="My alt text" loading="lazy" sizes="100vw" src="image.jpg" srcset="image.jpg 1x" />
</div>
<figcaption class="rsi-figcaption">My alt text</figcaption>
</figure>
Options
| Option | Type | Description |
| --------------------- | ---------------- | --------------------------------------------------------------------------------------------------------------------------------------------------- |
| urlBuilder
| Function | A function that takes the src
of an image and returns a new src
. |
| disableLazy
| Boolean | If true
, the loading
attribute of the img
element will be set to "eager"
. Otherwise, it will be set to "lazy"
. |
| defaultSizes
| String | The value for the sizes
attribute of the img
element. |
| elements.img
| Object | An object containing additional properties for the img
element. |
| elements.container
| Object | An object containing properties for the div
container element. If disable
is true
, the container will not be added. |
| elements.figcaption
| Object | An object containing properties for the figcaption
element. If disable
is true
, the figcaption
will not be added. |
| elements.figure
| Object | An object containing properties for the figure
element. If disable
is true
, the figure
will not be added. |
| srcSetSteps
| Array of numbers | An array of multipliers for generating the srcSet
attribute of the img
element. If not provided or empty, only the original src
will be used. |
These options can be passed to the rehype-semantic-images
plugin as part of the options
object. For example:
rehypeSemanticImages({
defaultSizes: "(min-width: 960px) 720px, 100vw",
disableLazy: false,
elements: {
container: { className: "custom-container", id: "containerID", disable: false },
figcaption: { className: "custom-figcaption", id: "figcaptionID", disable: false },
figure: { className: "custom-figure", id: "figureID", disable: false },
img: { className: "custom-image", id: "imageID" },
},
srcSetSteps: [1, 2, 3],
urlBuilder: (src) => `https://my-cdn.com/${src}`,
});
This will customize the top and bottom links according to the provided options.