unist-util-filter
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!Chatchat-badgechatunist utility to create a new tree with only nodes that pass a test.
Contents
* [`filter(tree[, options][, test])`](#filtertree-options-test)
* [`Options`](#options)
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 tounist-util-remove
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
unist-util-visit to remove
nodes.
To create trees, use unist-builder
unist-builder.Install
This package is ESM onlyesm. In Node.js (version 16+), install with npm:npm install unist-util-filter
In Deno with
esm.sh
esmsh:import {filter} from 'https://esm.sh/unist-util-filter@5'
In browsers with
esm.sh
esmsh:<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 identifierfilter
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 to filter
— configuration
— `unist-util-is` compatible test
Returns
New filtered tree (Node
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 typeOptions
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
— walk the tree
— walk the tree with a stack of parents
— create a new tree with all nodes mapped by a given function
— create a new tree by mapping (to an array) by a given function
— remove nodes from a tree that pass a test
— select nodes with CSS-like selectors
Contribute
Seecontributing.md
contributing in syntax-tree/.github
health for
ways to get started.
See support.md
support for ways to get help.This project has a code of conductcoc. By interacting with this repository, organization, or community you agree to abide by its terms.