Project: syntax-tree/unist-util-filter

Package: unist-util-filter@4.0.0

  1. Dependents: 35
  2. unist utility to create a new tree with nodes that pass a filter
  1. util 144
  2. utility 140
  3. unist 129
  4. tree 41
  5. ast 34
  6. unist-util 25
  7. node 25
  8. test 6
  9. filter 5


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unist utility to create a new tree with all nodes that pass the given test.


This package is ESM only: Node 12+ is needed to use it and it must be imported instead of required.


npm install unist-util-filter


import {u} from 'unist-builder'
import {filter} from 'unist-util-filter'

const tree = u('root', [
  u('leaf', '1'),
  u('node', [u('leaf', '2'), u('node', [u('leaf', '3')])]),
  u('leaf', '4')

const newTree = filter(tree, node => node.type !== 'leaf' || node.value % 2 === 0)

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


  type: 'root',
  children: [
    {type: 'node', children: [{type: 'leaf', value: '2'}]},
    {type: 'leaf', value: '4'}


This package exports the following identifiers: filter. There is no default export.

filter(tree[, options][, test])

Create a new tree consisting of copies of all nodes that pass test. The tree is walked in preorder (NLR), visiting the node itself, then its head, etc.


Node? — New filtered tree. null is returned if tree itself didn’t pass the test, or is cascaded away.


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