Project: syntax-tree/unist-builder

Package: unist-builder@3.0.0

  1. Dependents: 0
  2. unist utility to create a new trees with a nice syntax
  1. util 147
  2. utility 143
  3. unist 133
  4. tree 44
  5. ast 37
  6. syntax 28
  7. unist-util 25
  8. hyperscript 6
  9. dsl 5
  10. build 3


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unist utility to create trees with ease.


What is this?

This package is a hyperscript interface (like createElement from React and h from Vue and such) to help with creating unist trees.

When should I use this?

You can use this utility in your project when you generate 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 hastscript or xastscript when creating hast (HTML) or xast (XML) nodes.


This package is ESM only. In Node.js (version 12.20+, 14.14+, 16.0+, or 18.0+), install with npm:

npm install unist-builder

In Deno with esm.sh:

import {u} from 'https://esm.sh/unist-builder@3'

In browsers with esm.sh:

<script type="module">
  import {u} from 'https://esm.sh/unist-builder@3?bundle'


import {u} from 'unist-builder'

const tree = u('root', [
  u('subtree', {id: 1}),
  u('subtree', {id: 2}, [
    u('node', [u('leaf', 'leaf 1'), u('leaf', 'leaf 2')]),
    u('leaf', {id: 3}, 'leaf 3'),
    u('void', {id: 4})

console.dir(tree, {depth: null})

results in the following tree:

  type: 'root',
  children: [
    {type: 'subtree', id: 1},
      type: 'subtree',
      id: 2,
      children: [
          type: 'node',
          children: [
            {type: 'leaf', value: 'leaf 1'},
            {type: 'leaf', value: 'leaf 2'}
        {type: 'leaf', id: 3, value: 'leaf 3'},
        {type: 'void', id: 4}


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

u(type[, props][, children|value])

Build a node.


Built node (Node).


This package is fully typed with TypeScript. It exports the additional types Props and ChildrenOrValue.


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+, 16.0+, and 18.0+. Our projects sometimes work with older versions, but this is not guaranteed.


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 © Eugene Sharygin