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Project: syntax-tree/hast-util-to-estree

Package: hast-util-to-estree@1.3.1

  1. Dependencies: 8·Dependents: 0
  2. hast utility to transform to estree (JavaScript AST) JSX
  1. util 130
  2. utility 126
  3. unist 120
  4. html 109
  5. rehype 74
  6. hast 62
  7. hast-util 41
  8. mdx 25
  9. jsx 17
  10. javascript 17
  11. transform 8
  12. ecmascript 7
  13. change 4
  14. estree 4
  15. babel 2

hast-util-to-estree

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hast utility to transform a tree to estree JSX.

Install

npm:

npm install hast-util-to-estree

Use

Say we have the following HTML file, example.html:

<!doctype html>
<html lang=en>
<title>Hi!</title>
<link rel=stylesheet href=index.css>
<h1>Hello, world!</h1>
<a download style="width:1;height:10px"></a>
<!--commentz-->
<svg xmlns="http://www.w3.org/2000/svg">
  <title>SVG `&lt;ellipse&gt;` element</title>
  <ellipse
    cx="120"
    cy="70"
    rx="100"
    ry="50"
  />
</svg>
<script src="index.js"></script>

And our script, example.js, is:

var fs = require('fs')
var parse5 = require('parse5')
var fromParse5 = require('hast-util-from-parse5')
var toEstree = require('hast-util-to-estree')
var recast = require('recast')

var hast = fromParse5(parse5.parse(String(fs.readFileSync('example.html'))))

var estree = toEstree(hast)

estree.comments = null // `recast` doesn’t like comments on the root.
console.log(recast.prettyPrint(estree).code)

Now, node example (and prettier), yields:

;<>
  <html lang="en">
    <head>
      <title>{'Hi!'}</title>
      {'\n'}
      <link rel="stylesheet" href="index.css" />
      {'\n'}
    </head>
    <body>
      <h1>{'Hello, world!'}</h1>
      {'\n'}
      <a
        download
        style={{
          width: '1',
          height: '10px'
        }}
      />
      {'\n'}
      {/*commentz*/}
      {'\n'}
      <svg xmlns="http://www.w3.org/2000/svg">
        {'\n  '}
        <title>{'SVG `<ellipse>` element'}</title>
        {'\n  '}
        <ellipse cx="120" cy="70" rx="100" ry="50" />
        {'\n'}
      </svg>
      {'\n'}
      <script src="index.js" />
      {'\n'}
    </body>
  </html>
</>

API

toEstree(tree, options?)

Transform a hast tree to an estree (JSX).

options
Returns

estree — a Program node, whose last child in body is most likely an ExpressionStatement whose expression is a JSXFragment or a JSXElement.

Typically, there is only one node in body, however, this utility also supports embedded MDX nodes in the HTML (when mdast-util-mdx is used with mdast to parse markdown before passing its nodes through to hast). When MDX ESM import/exports are used, those nodes are added before the fragment or element in body.

Note

Comments are both attached to the tree in their neighbouring nodes (recast and babel style), and added as a comments array on the program node (espree style). You may have to do program.comments = null for certain compilers.

There aren’t many great estree serializers out there that support JSX. recast does a fine job. Or use estree-util-build-jsx to turn JSX into function calls and then serialize with whatever (astring, escodegen).

Security

You’re working with JavaScript. It’s not safe.

Contribute

See contributing.md in syntax-tree/.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.

License

MIT © Titus Wormer