syntax-tree/unist-util-modify-children

utility to modify direct children of a parent

unist-util-modify-children

unist utility to change children of a parent.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • modifyChildren(modifier)
  • Modifier
  • Modify
• Types
• Compatibility
• Related
• Contribute
• License

What is this?

This is a tiny utility that you can use to create a reusable function that modifies children.

When should I use this?

Probably never! Use unist-util-visit.

Install

This package is ESM only. In Node.js (version 16+), install with npm:

npm install unist-util-modify-children

In Deno with esm.sh:

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

In browsers with esm.sh:

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

Use

import u from 'unist-builder'
import {modifyChildren} from 'unist-util-modify-children'

const tree = u('root', [
  u('leaf', '1'),
  u('parent', [u('leaf', '2')]),
  u('leaf', '3')
])
const modify = modifyChildren(function (node, index, parent) {
  if (node.type === 'parent') {
    parent.children.splice(index, 1, {type: 'subtree', children: parent.children})
    return index + 1
  }
})

modify(tree)

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

Yields:

{
  type: 'root',
  children: [
    {type: 'leaf', value: '1'},
    {type: 'subtree', children: [{type: 'leaf', value: '2'}]},
    {type: 'leaf', value: '3'}
  ]
}

API

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

modifyChildren(modifier)

Wrap modifier to be called for each child in the nodes later given to modify.

Parameters

• modifier (Modifier) — callback called for each child in parent later given to modify

Returns

Modify children of parent (Modify).

Modifier

Callback called for each child in parent later given to modify (TypeScript type).

Parameters

• child (Node) — child of parent
• index (number) — position of child in parent
• parent (Node) — parent node

Returns

Position to move to next (optional) (number or undefined).

Modify

Modify children of parent (TypeScript type).

Parameters

• parent (Node) — parent node

Returns

Nothing (undefined).

Types

This package is fully typed with TypeScript. It exports the additional types Modifier and Modify.

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-modify-children@^4, compatible with Node.js 16.

Related

• unist-util-visit — walk the tree
• unist-util-visit-parents — walk the tree with a stack of parents
• unist-util-filter — create a new tree with all nodes that pass a test
• 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) with the given function
• unist-util-find-after — find a node after another node
• unist-util-find-before — find a node before another node
• unist-util-find-all-after — find all nodes after another node
• unist-util-find-all-before — find all nodes before another node
• unist-util-find-all-between — find all nodes between two nodes
• 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 © Titus Wormer