unist-util-filter
v5.0.1
Published
unist utility to create a new tree with nodes that pass a filter
Downloads
1,372,376
Readme
unist-util-filter
unist utility to create a new tree with only nodes that pass a test.
Contents
What is this?
This is a small utility that helps you clean a tree.
When should I use this?
You can use this utility to remove things from a tree.
This utility is very similar to unist-util-remove
, which
changes the given tree.
Modifying a tree like that utility does is much faster on larger documents.
You can also walk the tree with unist-util-visit
to remove
nodes.
To create trees, use unist-builder
.
Install
This package is ESM only. In Node.js (version 16+), install with npm:
npm install unist-util-filter
In Deno with esm.sh
:
import {filter} from 'https://esm.sh/unist-util-filter@5'
In browsers with esm.sh
:
<script type="module">
import {filter} from 'https://esm.sh/unist-util-filter@5?bundle'
</script>
Use
import {u} from 'unist-builder'
import {filter} from 'unist-util-filter'
const tree = u('root', [
u('leaf', '1'),
u('parent', [u('leaf', '2'), u('parent', [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: 'parent', children: [{type: 'leaf', value: '2'}]},
{type: 'leaf', value: '4'}
]
}
API
This package exports the identifier filter
.
There is no default export.
filter(tree[, options][, test])
Create a new tree
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 filteroptions
(Options
, optional) — configurationtest
(Test
, optional) —unist-util-is
compatible test
Returns
New filtered tree (Node
or undefined
).
undefined
is returned if tree
itself didn’t pass the test, or is cascaded
away.
Options
Configuration (TypeScript type).
Fields
cascade
(boolean
, default:true
) — whether to drop parent nodes if they had children, but all their children were filtered out
Types
This package is fully typed with TypeScript.
It exports the additional type Options
.
Compatibility
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, unist-util-filter@^5
,
compatible with Node.js 16.
Related
unist-util-visit
— walk the treeunist-util-visit-parents
— walk the tree with a stack of parentsunist-util-map
— create a new tree with all nodes mapped by a given functionunist-util-flatmap
— create a new tree by mapping (to an array) by a given functionunist-util-remove
— remove nodes from a tree that pass a testunist-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