syntax-tree/unist-util-remove

utility to remove nodes from a tree

unist-util-remove

unist utility to remove all nodes that pass a test from the tree.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • remove(tree[, options], test)
  • Options
• Types
• Compatibility
• Related
• Contribute
• License

What is this?

This is a small utility that helps you clean a tree by removing some stuff.

When should I use this?

You can use this utility to remove things from a tree. This utility is very similar to unist-util-filter, which creates a new tree. Modifying a tree like this utility unist-util-remove does is much faster on larger documents though.

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-remove

In Deno with esm.sh:

import {remove} from 'https://esm.sh/unist-util-remove@4'

In browsers with esm.sh:

<script type="module">
  import {remove} from 'https://esm.sh/unist-util-remove@4?bundle'
</script>

Use

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

const tree = u('root', [
  u('leaf', '1'),
  u('parent', [
    u('leaf', '2'),
    u('parent', [u('leaf', '3'), u('other', '4')]),
    u('parent', [u('leaf', '5')])
  ]),
  u('leaf', '6')
])

// Remove all nodes of type `leaf`.
remove(tree, 'leaf')

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

Yields:

{
  type: 'root',
  children: [
    {
      type: 'parent',
      children: [{type: 'parent', children: [{type: 'other', value: '4'}]}]
    }
  ]
}

👉 Note: the parent of leaf 5 is also removed, options.cascade can change that.

API

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

remove(tree[, options], test)

Change the given tree by removing all nodes that pass test.

tree itself is never tested. The tree is walked in preorder (NLR), visiting the node itself, then its head, etc.

Parameters

• tree (Node) — tree to change
• options (Options, optional) — configuration
• test (Test, optional) — unist-util-is compatible test

Returns

Nothing (undefined).

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-remove@^4, compatible with Node.js 16.

Related

• unist-util-filter — create a new tree with all nodes that pass the given function
• unist-util-flatmap — create a new tree by expanding a node into many
• unist-util-map — create a new tree by mapping nodes
• unist-util-select — select nodes with CSS-like selectors
• unist-util-visit — walk the tree
• unist-builder — create trees

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, organisation, or community you agree to abide by its terms.

License

MIT © Eugene Sharygin

unist-util-remove's Issues

Update unist-util-is

Hi! 👋

I was planning on updating this, but unist-util-is removed equality checks in favour of partial property checks (syntax-tree/unist-util-is#1, I remember we talked about that issue, maybe on Gitter?)

Anyway, this project uses equality checks a lot (in tests and examples at least). So what should we do?

a) overwrite partial checks with a type (e.g., remove(tree, {type: 'listItem'})) as an equality tests?
b) expect people to pass in equality checks themselves (e.g., remove(tree, n => n === someNode)).

Add index.d.ts

Subject of the feature

As for the other unist-util-*, please consider adding index.d.ts