xast utility to create trees with ease.
- What is this?
- When should I use this?
- Install
- Use
- API
- Syntax tree
- JSX
- Types
- Compatibility
- Security
- Related
- Contribute
- License
This package is a hyperscript interface (like createElement
from React and
such) to help with creating xast trees.
You can use this utility in your project when you generate xast syntax trees with code. It helps because it replaces most of the repetition otherwise needed in a syntax tree with function calls.
You can instead use unist-builder
when creating any unist nodes and
hastscript
when creating hast (HTML) nodes.
This package is ESM only. In Node.js (version 16+), install with npm:
npm install xastscript
In Deno with esm.sh
:
import {x} from 'https://esm.sh/xastscript@4'
In browsers with esm.sh
:
<script type="module">
import {x} from 'https://esm.sh/xastscript@4?bundle'
</script>
import {u} from 'unist-builder'
import {x} from 'xastscript'
// Children as an array:
console.log(
x('album', {id: 123}, [
x('name', 'Born in the U.S.A.'),
x('artist', 'Bruce Springsteen'),
x('releasedate', '1984-04-06')
])
)
// Children as arguments:
console.log(
x(
'album',
{id: 123},
x('name', 'Exile in Guyville'),
x('artist', 'Liz Phair'),
x('releasedate', '1993-06-22')
)
)
// For other xast nodes, such as comments, instructions, doctypes, or cdata
// can be created with unist-builder:
console.log(
x(null, [
u('instruction', {name: 'xml'}, 'version="1.0" encoding="UTF-8"'),
x('album', [
u('comment', 'Great album!'),
x('name', 'Born in the U.S.A.'),
x('description', [u('cdata', '3 < 5 & 8 > 13')])
])
])
)
Yields:
{
type: 'element',
name: 'album',
attributes: {id: '123'},
children: [
{
type: 'element',
name: 'name',
attributes: {},
children: [{type: 'text', value: 'Born in the U.S.A.'}]
},
{
type: 'element',
name: 'artist',
attributes: {},
children: [{type: 'text', value: 'Bruce Springsteen'}]
},
{
type: 'element',
name: 'releasedate',
attributes: {},
children: [{type: 'text', value: '1984-04-06'}]
}
]
}
{
type: 'element',
name: 'album',
attributes: {id: '123'},
children: [
{
type: 'element',
name: 'name',
attributes: {},
children: [{type: 'text', value: 'Exile in Guyville'}]
},
{
type: 'element',
name: 'artist',
attributes: {},
children: [{type: 'text', value: 'Liz Phair'}]
},
{
type: 'element',
name: 'releasedate',
attributes: {},
children: [{type: 'text', value: '1993-06-22'}]
}
]
}
{
type: 'root',
children: [
{type: 'instruction', name: 'xml', value: 'version="1.0" encoding="UTF-8"'},
{
type: 'element',
name: 'album',
attributes: {},
children: [
{type: 'comment', value: 'Great album!'},
{
type: 'element',
name: 'name',
attributes: {},
children: [{type: 'text', value: 'Born in the U.S.A.'}]
},
{
type: 'element',
name: 'description',
attributes: {},
children: [{type: 'cdata', value: '3 < 5 & 8 > 13'}]
}
]
}
]
}
This package exports the identifier x
.
There is no default export.
The export map supports the automatic JSX runtime.
You can pass xastscript
to your build tool (TypeScript, Babel, SWC) with an
importSource
option or similar.
Create xast trees.
x(): root
x(null[, …children]): root
x(name[, attributes][, …children]): element
Qualified name (string
, optional).
Case sensitive and can contain a namespace prefix (such as rdf:RDF
).
When string, an Element
is built.
When nullish, a Root
is built instead.
Attributes of the element (Attributes
, optional).
Children of the node (Array<Child>
or Child
, optional).
Created tree (Result
).
Element
when a name
is passed, otherwise Root
.
Map of attributes (TypeScript type).
Nullish (null
or undefined
) or NaN
values are ignored, other values are
turned to strings.
type Attributes = Record<string, boolean | number | string | null | undefined>
(Lists of) children (TypeScript type).
When strings or numbers are encountered, they are turned into Text
nodes.
Root
nodes are treated as “fragments”, meaning that their children
are used instead.
type Child =
| Array<Node | boolean | number | string | null | undefined>
| Node
| boolean
| number
| string
| null
| undefined
Result from a x
call (TypeScript type).
type Result = Element | Root
The syntax tree is xast.
This package can be used with JSX.
You should use the automatic JSX runtime set to xastscript
.
🪦 Legacy: you can also use the classic JSX runtime, but this is not recommended. To do so, import
x
yourself and define it as the pragma (plus set the fragment tonull
).
The Use example above (omitting the second) can then be written like so:
/** @jsxImportSource xastscript */
import {u} from 'unist-builder'
console.log(
<album id={123}>
<name>Born in the U.S.A.</name>
<artist>Bruce Springsteen</artist>
<releasedate>1984-04-06</releasedate>
</album>
)
console.log(
<>
{u('instruction', {name: 'xml'}, 'version="1.0" encoding="UTF-8"')}
<album>
{u('comment', 'Great album!')}
<name>Born in the U.S.A.</name>
<description>{u('cdata', '3 < 5 & 8 > 13')}</description>
</album>
</>
)
This package is fully typed with TypeScript.
It exports the additional types Attributes
,
Child
, and Result
.
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, xastscript@^4
, compatible
with Node.js 16.
XML can be a dangerous language: don’t trust user-provided data.
unist-builder
— create any unist treehastscript
— create a hast treexast-util-to-xml
— serialize xast as XMLxast-util-from-xml
— parse xast from XMLhast-util-to-xast
— transform hast to xast
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.