unist-util-map

unist utility to create a new tree by mapping all nodes with the given function.

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-map

Use

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

var tree = u('tree', [
  u('leaf', 'leaf 1'),
  u('node', [u('leaf', 'leaf 2')]),
  u('void'),
  u('leaf', 'leaf 3')
])

var next = map(tree, function(node) {
  return node.type === 'leaf'
    ? Object.assign({}, node, {value: 'CHANGED'})
    : node
})

console.dir(next, {depth: null})

Yields:

{
  type: 'tree',
  children: [
    {type: 'leaf', value: 'CHANGED'},
    {type: 'node', children: [{type: 'leaf', value: 'CHANGED'}]},
    {type: 'void'},
    {type: 'leaf', value: 'CHANGED'}
  ]
}

…note that tree is not mutated.

API

This package exports the following identifiers: map. There is no default export.

map(tree, mapFn)

Create a new tree by mapping all nodes with the given function.

Parameters

• tree (Node) — Tree to map
• callback (Function) — Function that returns a new node

Returns

Node — New mapped tree.

function mapFn(node[, index, parent])

Function called with a node to produce a new node.

Parameters

• node (Node) — Current node being processed
• index (number?) — Index of node, or null
• parent (Node?) — Parent of node, or null

Returns

Node — Node to be used in the new tree. Its children are not used: if the original node has children, those are mapped.

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-remove — Remove nodes from trees
• unist-util-select — Select nodes with CSS-like selectors
• unist-util-visit — Recursively walk over nodes
• unist-builder — Creating 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, organization, or community you agree to abide by its terms.

License

MIT © azu