unist-util-position

What is unist-util-position?

The unist-util-position package is a utility for working with positional information in unist syntax trees. It provides functions to get and manipulate positions of nodes within these trees, which is useful for tasks such as error reporting, syntax highlighting, and more.

What are unist-util-position's main functionalities?

position.start

This feature retrieves the starting position of a node. The code sample demonstrates how to use the `position.start` function to get the starting line and column of a node.

const position = require('unist-util-position');
const node = { position: { start: { line: 1, column: 1 }, end: { line: 1, column: 5 } } };
console.log(position.start(node)); // { line: 1, column: 1 }

position.end

This feature retrieves the ending position of a node. The code sample shows how to use the `position.end` function to get the ending line and column of a node.

const position = require('unist-util-position');
const node = { position: { start: { line: 1, column: 1 }, end: { line: 1, column: 5 } } };
console.log(position.end(node)); // { line: 1, column: 5 }

position.point

This feature normalizes a point object. The code sample demonstrates how to use the `position.point` function to ensure a point object has the correct structure.

const position = require('unist-util-position');
const point = { line: 1, column: 1 };
console.log(position.point(point)); // { line: 1, column: 1 }

Other packages similar to unist-util-position

unist-util-visit

The unist-util-visit package is used to recursively walk through unist syntax trees. While it doesn't specifically handle positional information, it can be used in conjunction with unist-util-position to traverse nodes and then retrieve their positions.

unist-util-find

The unist-util-find package helps in finding nodes in unist syntax trees based on certain criteria. It can be used to locate nodes and then unist-util-position can be used to get their positional information.

unist-util-select

The unist-util-select package allows for selecting nodes in unist syntax trees using CSS-like selectors. Once nodes are selected, unist-util-position can be used to get their positions. This package is useful for more complex queries within the tree.

README

unist-util-position

unist utility to get positional info of nodes.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • position(node)
  • pointEnd(node)
  • pointStart(node)
• Types
• Compatibility
• Related
• Contribute
• License

What is this?

This utility helps with accessing positional info on a potentially dirty tree.

When should I use this?

The positional info is typically consistent and proper in unist trees generated by our ecosystem, but, user plugins could mess that up. If you’re making a reusable plugin, and accessing the positional info often, you might want to guard against that by using this utility.

You might also find the utility unist-util-generated useful to check whether a node is considered to be generated (not in the original input file).

You might also enjoy unist-util-stringify-position when you want to display positional info to users.

Install

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

npm install unist-util-position

In Deno with esm.sh:

import {position, pointStart, pointEnd} from 'https://esm.sh/unist-util-position@4'

In browsers with esm.sh:

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

Use

import {fromMarkdown} from 'mdast-util-from-markdown'
import {position, pointStart, pointEnd} from 'unist-util-position'

const tree = fromMarkdown('# foo\n\n* bar\n')

console.log(position(tree))
console.log(pointStart(tree))
console.log(pointEnd(tree))

Yields:

{start: {line: 1, column: 1, offset: 0}, end: {line: 4, column: 1, offset: 13}}
{line: 1, column: 1, offset: 0}
{line: 4, column: 1, offset: 13}

API

This package exports the identifiers pointEnd, pointStart, and position. There is no default export.

position(node)

Get the positional info of node.

Parameters

• node (Node) — node

Returns

Position (Position).

pointEnd(node)

Get the ending point of node.

Parameters

• node (Node) — node

Returns

Point (Point).

pointStart(node)

Get the starting point of node.

Parameters

• node (Node) — node

Returns

Point (Point).

Types

This package is fully typed with TypeScript. It exports no additional types.

Compatibility

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

Related

• unist-util-stringify-position — serialize a node, position, or point as a human readable location
• unist-util-position-from-estree — get a position from an estree node
• unist-util-remove-position — remove positions from tree
• unist-util-generated — check if a node is generated
• unist-util-source — get the source of a node

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