unist-util-filter

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

Install

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

npm:

npm install unist-util-filter

Use

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})

Yields:

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

API

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.

Parameters

• tree (Node?) — Tree to filter
• options.cascade (boolean, default: true) — Whether to drop parent nodes if they had children, but all their children were filtered out
• test (Test, optional) — is-compatible test (such as a type)

Returns

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

Related

• unist-util-visit — Recursively walk over nodes
• unist-util-visit-parents — Like visit, but with a stack of parents
• unist-util-map — Create a new tree with all nodes mapped by a given function
• unist-util-flatmap — Create a new tree by mapping (to an array) by a given function
• unist-util-remove — Remove nodes from a tree that pass a test
• unist-util-select — Select nodes with CSS-like selectors

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 © Eugene Sharygin