vfile-location

What is vfile-location?

The vfile-location npm package is a utility tool for working with virtual file objects, specifically designed to map positions in a virtual file to line and column-based locations. This is particularly useful when dealing with transformations or manipulations of text where tracking positions within the original and modified content is necessary.

What are vfile-location's main functionalities?

Location Mapping

This feature allows you to convert between line and column-based locations and absolute positions within a file's content. The `toOffset` method converts a line and column object to a zero-based offset, and the `toPoint` method converts an offset back to a line and column object.

const vfileLocation = require('vfile-location');
const text = 'Hello\nWorld';
const location = vfileLocation(text);

// Get position from line and column
const offset = location.toOffset({line: 2, column: 1}); // Returns 7

// Get line and column from position
const point = location.toPoint(offset); // Returns {line: 2, column: 1}

Other packages similar to vfile-location

line-column

The 'line-column' npm package provides similar functionality to vfile-location, allowing users to find the line and column position from a character index and vice versa. It differs in its API design and additional options for customization, such as setting the origin index.

columnify

While primarily focused on creating text-based columns for display, 'columnify' can also be used to manage text positions similarly to vfile-location. It is more specialized in creating aligned text output but includes position tracking as part of its layout capabilities.

README

vfile-location

vfile utility to convert between positional (line and column-based) and offsets (range-based) locations.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • location(file)
  • Location
• Types
• Compatibility
• Contribute
• License

What is this?

This is a tiny but useful package to convert between arbitrary places in a file.

When should I use this?

This utility is useful when ASTs nodes don’t cut it. For example, when you are making a lint rule that looks for dangerous characters in a file, which you accomplish by searching the raw file value, and still want to report it to users.

Install

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

npm install vfile-location

In Deno with esm.sh:

import {location} from 'https://esm.sh/vfile-location@5'

In browsers with esm.sh:

<script type="module">
  import {location} from 'https://esm.sh/vfile-location@5?bundle'
</script>

Use

import {VFile} from 'vfile'
import {location} from 'vfile-location'

const place = location(new VFile('foo\nbar\nbaz'))

const offset = place.toOffset({line: 3, column: 3}) // => 10
place.toPoint(offset) // => {line: 3, column: 3, offset: 10}

API

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

location(file)

Create an index of the given document to translate between line/column and offset based positional info.

Parameters

• file (VFile, Buffer, or string) — file to index

Returns

Accessors for index (Location).

Location

Accessors for index (TypeScript type).

Fields

• toPoint ((offset: number) => Point | undefined) — get the line/column based Point for offset in the bound indices
• toOffset ((point: Point) => number | undefined) — get the offset from a line/column based Point in the bound indices

Types

This package is fully typed with TypeScript. It exports the additional type Location.

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, vfile-location@^5, compatible with Node.js 16.

Contribute

See contributing.md in vfile/.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