rehype-javascript-to-bottom

rehype plugin to move JavaScript <script>s to the end of the body.

What is this?
When should I use this?
Install
Use
API
- unified().use(rehypeJavaScriptToBottom[, options])
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.

unified

Project: rehypejs/rehype-minify

Package: rehype-javascript-to-bottom@3.0.0