Project: syntax-tree/xast-util-to-xml

Package: xast-util-to-xml@3.0.0

  1. xast utility to serialize to XML
  1. util 146
  2. utility 142
  3. unist 132
  4. xml 10
  5. xast 8
  6. xast-util 7


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xast utility to serialize as XML.


What is this?

This package is a utility that turns a xast tree into a string of XML.

When should I use this?

You can use this utility when you want to get the serialized XML that is represented by the syntax tree, either because you’re done with the syntax tree, or because you’re integrating with another tool that does not support syntax trees.

This utility has options to configure how the XML is serialized. These options help when building tools that make output pretty (such as formatters) or ugly (such as minifiers).

The utility xast-util-from-xml does the inverse of this utility. It turns XML into xast.

The utility hast-util-to-html does the same as this utility but for HTML: it turns hast into HTML.


This package is ESM only. In Node.js (version 16+), install with npm:

npm install xast-util-to-xml

In Deno with esm.sh:

import {toXml} from 'https://esm.sh/xast-util-to-xml@4'

In browsers with esm.sh:

<script type="module">
  import {toXml} from 'https://esm.sh/xast-util-to-xml@4?bundle'


import {u} from 'unist-builder'
import {x} from 'xastscript'
import {toXml} from 'xast-util-to-xml'

const tree = u('root', [
  u('instruction', {name: 'xml'}, 'version="1.0" encoding="utf-8"'),
  u('text', '\n'),
  x('ncx', {xmlns: 'http://www.daisy.org/z3986/2005/ncx/', version: '2005-1'}, [
    u('text', '\n  '),
    x('head', [
      u('text', '\n    '),
      x('meta', {name: 'dtb:uid', content: 'urn:isbn:9781234567891'}),
      u('text', '\n  ')
    u('text', '\n  '),
    x('docTitle', [x('text', 'A Christmas Carol')]),
    u('text', '\n  '),
    x('docAuthor', [x('text', 'Charles Dickens')]),
    u('text', '\n')



<?xml version="1.0" encoding="utf-8"?>
<ncx xmlns="http://www.daisy.org/z3986/2005/ncx/" version="2005-1">
    <meta name="dtb:uid" content="urn:isbn:9781234567891"></meta>
  <docTitle><text>A Christmas Carol</text></docTitle>
  <docAuthor><text>Charles Dickens</text></docAuthor>


This package exports the identifier toXml. There is no default export.

toXml(tree[, options])

Serialize a xast tree to XML.


Serialized XML (string).


Configuration (TypeScript type).


Allow raw nodes and insert them as raw XML (boolean, default: false).

When false, Raw nodes are encoded.

⚠️ Danger: only set this if you completely trust the content.


Close elements without any content with slash (/) on the opening tag instead of an end tag: <circle /> instead of <circle></circle> (boolean, default: false).

See tightClose to control whether a space is used before the slash.


Preferred quote to use (Quote, default: '"').


Use the other quote if that results in less bytes (boolean, default: false).


Do not use an extra space when closing self-closing elements: <circle/> instead of <circle /> (boolean, default: false).

👉 Note: only used if closeEmptyElements: true.


XML quotes for attribute values (TypeScript type).

type Quote = '"' | "'"


Raw (TypeScript type).

import type {Data, Literal} from 'xast'

interface Raw extends Literal {
  type: 'raw'
  data?: RawData | undefined

export interface RawData extends Data {}


This package is fully typed with TypeScript. It exports the additional types Options, Quote, and Raw.

It also registers the node type with @types/xast. If you’re working with the syntax tree, make sure to import this utility somewhere in your types, as that registers the new node types in the tree.

 * @typedef {import('xast-util-to-xml')}

import {visit} from 'unist-util-visit'

/** @type {import('xast').Root} */
const tree = getXastNodeSomeHow()

visit(tree, function (node) {
  // `node` can now be a raw node.


Projects maintained by the unified collective are compatible with maintained versions of Node.js.

When we cut a new major release, we drop support for unmaintained versions of Node. This means we try to keep the current release line, xast-util-to-xml@^4, compatible with Node.js 16.


XML can be a dangerous language: don’t trust user-provided data.


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.


MIT © Titus Wormer