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unist utility to create an index from certain nodes.

• What is this?
• When should I use this?
• Install
• Use
• API
  • Index(prop|keyFunction[, tree[, test]])
  • KeyFunction
  • Test
• Types
• Compatibility
• Related
• Contribute
• License

This utility creates a mutable index data structure, that maps property valuesor computed keys, to nodes.For example, you can use this to index all (footnote) definitions in a tree,or all headings of a certain rank, to later retrieve them without having to walkthe tree each time.

This is a utility that helps you deal with indexing the tree.It’s pretty small, and you can definitely do it yourself, but this littlewrapper makes it all a bit easier.

This package isESM only.In Node.js (version 16+), install withnpm:

npm install unist-util-index

In Deno withesm.sh:

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

In browsers withesm.sh:

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

importfsfrom'node:fs/promises'import{fromMarkdown}from'mdast-util-from-markdown'import{toString}from'mdast-util-to-string'import{Index}from'unist-util-index'// Parse and read this repo’s readme:consttree=fromMarkdown(awaitfs.readFile('readme.md'))// Index on heading depth:constindexOnDepth=newIndex('depth',tree,'heading')console.log(indexOnDepth.get(2).map(function(d){returntoString(d)}))// Index on definition identifier:constindexOnIdentifier=newIndex('identifier',tree,'definition')console.log(indexOnIdentifier.get('unist').map(function(node){returnnode.url}))

Yields:

['Contents','What is this?','When should I use this?','Install','Use','API','Types','Compatibility','Related','Contribute','License']['https://github.com/syntax-tree/unist']

This package exports the identifierIndex.There is no default export.

Create a mutable index data structure, that maps property values or computedkeys, to nodes.

Iftree is given, the index is initialized with all nodes, optionallyfiltered bytest.

• prop (string)— field to look up in each node to find keys
• keyFunction (KeyFunction)— function called with each node to calculate keys
• tree (Node, optional)— tree to index
• test (Test, optional)—unist-util-is compatible test

Instance (Index).

Get nodes bykey.

• key (unknown)— key to retrieve, can be anything that can be used as a key in aMap

List of zero or more nodes (Array<Node>).

Addnode to the index (if not already present).

• node (Node)— node to index

Current instance (Index).

Removenode from the index (if present).

• node (Node)— node to remove

Current instance (Index).

Function called with every added node to calculate the key to index on(TypeScript type).

• node (Node)— node to calculate a key for

Key to index on (unknown).

Can be anything that can be used as a key in aMap.

unist-util-is compatible test (TypeScript type).

This package is fully typed withTypeScript.It exports the additional typesKeyFunction andTest.

Projects maintained by the unified collective are compatible with maintainedversions of Node.js.

When we cut a new major release, we drop support for unmaintained versions ofNode.This means we try to keep the current release line,unist-util-index@^4,compatible with Node.js 16.

• unist-util-is— utility to check if a node passes a test
• unist-util-visit— utility to recursively walk over nodes
• unist-util-select— select nodes with CSS-like selectors

Seecontributing.md insyntax-tree/.github forways to get started.Seesupport.md for ways to get help.

This project has aCode of Conduct.By interacting with this repository, organisation, or community you agree toabide by its terms.

MIT © Eugene Sharygin