rehype-javascript-to-bottom
rehype plugin to move JavaScript <script>
s to the end of the body.
Contents
- What is this?
- When should I use this?
- Install
- Use
- API
- Example
- Syntax
- Syntax tree
- Types
- Compatibility
- Security
- Contribute
- License
What is this?
This package is a plugin that can improve performance by decreasing the time to first render.
When should I use this?
You can use this plugin when you want to improve the speed of HTML documents.
Install
This package is ESM only. In Node.js (version 12.20+, 14.14+, or 16.0+), install with npm:
npm install rehype-javascript-to-bottom
In Deno with esm.sh
:
import rehypeJavaScriptToBottom from 'https://esm.sh/rehype-javascript-to-bottom@3'
In browsers with esm.sh
:
<script type="module">
import rehypeJavaScriptToBottom from 'https://esm.sh/rehype-javascript-to-bottom@3?bundle'
</script>
Use
On the API:
import {read} from 'to-vfile'
import {unified} from 'unified'
import rehypeParse from 'rehype-parse'
import rehypeStringify from 'rehype-stringify'
import rehypeJavaScriptToBottom from 'rehype-javascript-to-bottom'
main()
async function main() {
const file = await unified()
.use(rehypeParse)
.use(rehypeJavaScriptToBottom)
.use(rehypeStringify)
.process(await read('index.html'))
console.log(String(file))
}
On the CLI:
rehype input.html --use rehype-javascript-to-bottom --output output.html
On the CLI in a config file (here a package.json
):
…
"rehype": {
"plugins": [
…
+ "rehype-javascript-to-bottom",
…
]
}
…
API
This package exports no identifiers. The default export is rehypeJavaScriptToBottom
.
unified().use(rehypeJavaScriptToBottom[, options])
Move JavaScript <script>
s to the end of <body>
.
options
Configuration (optional).
options.filter
Function called with each checked script that can return true
to move the script or false
if not.
Example
In
<!doctype html><html><head><script src="index.js"></script></head><body></body></html>
Out
<!doctype html><html><head></head><body><script src="index.js"></script></body></html>
Syntax
HTML is handled according to WHATWG HTML (the living standard), which is also followed by browsers such as Chrome and Firefox.
Syntax tree
The syntax tree format used is hast
.
Types
This package is fully typed with TypeScript.
Compatibility
Projects maintained by the unified collective are compatible with all maintained versions of Node.js. As of now, that is Node.js 12.20+, 14.14+, and 16.0+. Our projects sometimes work with older versions, but this is not guaranteed.
Security
As rehype works on HTML, and improper use of HTML can open you up to a cross-site scripting (XSS) attack, use of rehype can also be unsafe. Use rehype-sanitize
to make the tree safe.
Contribute
See contributing.md
in rehypejs/.github
for ways to get started. See support.md
for ways to get help.
This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.