unist-util-visit

unist utility to walk the tree.

Contents

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

What is this?

This is a very important utility for working with unist as it lets you walk the tree.

When should I use this?

You can use this utility when you want to walk the tree. You can use unist-util-visit-parents if you care about the entire stack of parents.

Install

This package is ESM only. In Node.js (version 12.20+, 14.14+, 16.0+, 18.0+), install with npm:

npm install unist-util-visit

In Deno with esm.sh:

import {visit} from "https://esm.sh/unist-util-visit@4"

In browsers with esm.sh:

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

Use

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

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

visit(tree, 'leaf', (node) => {
  console.log(node)
})

Yields:

{type: 'leaf', value: '1'}
{type: 'leaf', value: '2'}
{type: 'leaf', value: '3'}

API

This package exports the identifiers visit, CONTINUE, SKIP, and EXIT. There is no default export.

visit(tree[, test], visitor[, reverse])

This function works exactly the same as unist-util-visit-parents, but visitor has a different signature.

next? = visitor(node, index, parent)

Instead of being passed an array of ancestors, visitor is called with the node’s index and its parent.

Please see unist-util-visit-parents.

Types

This package is fully typed with TypeScript. It exports the additional types Test, VisitorResult, and Visitor.

It also exports the types BuildVisitor<Tree extends Node = Node, Check extends Test = string> to properly type visitors from a tree and a test, from unist-util-visit-parents/complex-types.d.ts.

Compatibility

Projects maintained by the unified collective are compatible with all maintained versions of Node.js. As of now, that is Node.js 12.20+, 14.14+, 16.0+, and 18.0+. Our projects sometimes work with older versions, but this is not guaranteed.

Related

• 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-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