vfile

What is vfile?

The vfile npm package is a virtual file format for text processing systems, which allows for the manipulation and handling of file-related information in a structured and consistent way. It is commonly used in projects involving the processing of markdown, text, and similar content, providing a standardized interface for plugins and utilities.

What are vfile's main functionalities?

Creating and modifying virtual files

This feature allows users to create a new virtual file and modify its contents. The example demonstrates creating a vfile with initial content and then appending additional text to it.

const vfile = require('vfile');

const file = vfile({path: './example.txt', contents: 'Hello, world!'});
file.contents += ' Modified content.';
console.log(file.contents);

Accessing file metadata

This feature enables users to access metadata of the file such as the path and basename. The example shows how to create a vfile and retrieve its path and basename properties.

const vfile = require('vfile');

const file = vfile({path: './example.txt', contents: 'Hello, world!'});
console.log(file.path); // Outputs: './example.txt'
console.log(file.basename); // Outputs: 'example.txt'

Handling errors and messages

This feature is useful for adding error or warning messages to a file, which can be particularly helpful in linting tools or compilers. The example demonstrates adding an error message to a vfile and logging all associated messages.

const vfile = require('vfile');

const file = vfile();
file.message('Unknown error', {line: 1, column: 1});
console.log(file.messages);

Other packages similar to vfile

vinyl

Vinyl is a virtual file format that is often used in the gulp build system. It is similar to vfile in that it represents file objects in a virtual form, but it is more focused on being used with streams, particularly in the context of gulp's pipelines.

mem-fs

mem-fs provides an in-memory file system which stores file representations similar to vfile. While vfile is designed for text processing with a focus on linting and transformation, mem-fs is geared more towards temporary storage and manipulation of files in memory during tasks like scaffolding or testing.

README

vfile is a small and browser friendly virtual file format that tracks metadata about files (such as its path and value) and lint messages.

Contents

• unified
• What is this?
• When should I use this?
• Install
• Use
• API
  • VFile(options?)
  • file.value
  • file.cwd
  • file.path
  • file.dirname
  • file.basename
  • file.extname
  • file.stem
  • file.history
  • file.messages
  • file.data
  • VFile#toString(encoding?)
  • VFile#message(reason[, position][, origin])
  • VFile#info(reason[, position][, origin])
  • VFile#fail(reason[, position][, origin])
  • Well-known fields
• List of utilities
• Reporters
• Types
• Compatibility
• Contribute
• Sponsor
• Acknowledgments
• License

unified

vfile is part of the unified collective.

• for more about us, see unifiedjs.com
• for how the collective is governed, see unifiedjs/collective
• for updates, see @unifiedjs on Twitter

What is this?

This package provides a virtual file format. It exposes an API to access the file value, path, metadata about the file, and specifically supports attaching lint messages and errors to certain places in these files.

When should I use this?

The virtual file format is useful when dealing with the concept of files in places where you might not be able to access the file system. The message API is particularly useful when making things that check files (as in, linting).

vfile is made for unified, which amongst other things checks files. However, vfile can be used in other projects that deal with parsing, transforming, and serializing data, to build linters, compilers, static site generators, and other build tools.

This is different from the excellent vinyl in that vfile has a smaller API, a smaller size, and focuses on messages.

Install

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

npm install vfile

In Deno with esm.sh:

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

In browsers with esm.sh:

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

Use

import {VFile} from 'vfile'

const file = new VFile({
  path: '~/example.txt',
  value: 'Alpha *braavo* charlie.'
})

console.log(file.path) // => '~/example.txt'
console.log(file.dirname) // => '~'

file.extname = '.md'

console.log(file.basename) // => 'example.md'

file.basename = 'index.text'

console.log(file.history) // => ['~/example.txt', '~/example.md', '~/index.text']

file.message('Unexpected unknown word `braavo`, did you mean `bravo`?', {
  line: 1,
  column: 8
})

console.log(file.messages)

Yields:

[
  [~/index.text:1:8: Unexpected unknown word `braavo`, did you mean `bravo`?] {
    reason: 'Unexpected unknown word `braavo`, did you mean `bravo`?',
    line: 1,
    column: 8,
    source: null,
    ruleId: null,
    position: {start: [Object], end: [Object]},
    file: '~/index.text',
    fatal: false
  }
]

API

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

VFile(options?)

Create a new virtual file.

• if options is string or Buffer, it’s treated as {value: options}
• if options is a URL, it’s treated as {path: options}
• if options is a VFile, shallow copies its data over to the new file

All fields in options are set on the newly created VFile.

Path related fields are set in the following order (least specific to most specific): history, path, basename, stem, extname, dirname.

It’s not possible to set either dirname or extname without setting either history, path, basename, or stem as well.

Example

new VFile()
new VFile('console.log("alpha");')
new VFile(Buffer.from('exit 1'))
new VFile({path: path.join('path', 'to', 'readme.md')})
new VFile({stem: 'readme', extname: '.md', dirname: path.join('path', 'to')})
new VFile({other: 'properties', are: 'copied', ov: {e: 'r'}})

file.value

Raw value (Buffer, string, null).

file.cwd

Base of path (string, default: process.cwd() or '/' in browsers).

file.path

Get or set the full path (string?, example: '~/index.min.js'). Cannot be nullified. You can set a file URL (a URL object with a file: protocol) which will be turned into a path with url.fileURLToPath.

file.dirname

Get or set the parent path (string?, example: '~'). Cannot be set if there’s no path yet.

file.basename

Get or set the basename (including extname) (string?, example: 'index.min.js'). Cannot contain path separators ('/' on unix, macOS, and browsers, '\' on windows). Cannot be nullified (use file.path = file.dirname instead).

file.extname

Get or set the extname (including dot) (string?, example: '.js'). Cannot contain path separators ('/' on unix, macOS, and browsers, '\' on windows). Cannot be set if there’s no path yet.

file.stem

Get or set the stem (basename w/o extname) (string?, example: 'index.min'). Cannot contain path separators ('/' on unix, macOS, and browsers, '\' on windows). Cannot be nullified.

file.history

List of filepaths the file moved between (Array<string>). The first is the original path and the last is the current path.

file.messages

List of messages associated with the file (Array<VFileMessage>).

file.data

Place to store custom information (Record<string, unknown>, default: {}). It’s OK to store custom data directly on the file but moving it to data is recommended.

VFile#toString(encoding?)

Serialize the file. When value is a Buffer, encoding is a character encoding to understand it as (string, default: 'utf8').

Returns

Serialized file (string).

VFile#message(reason[, position][, origin])

Constructs a new VFileMessage, where fatal is set to false, and associates it with the file by adding it to file.messages and setting message.file to the current filepath.

Parameters

• reason (string or Error) — human readable reason for the message, uses the stack and message of the error if given
• place (Node, Position, or Point, optional) — place where the message occurred in the file
• origin (string?, optional, example: 'my-npm-package:my-rule-name') — computer readable reason for the message

Returns

Message (VFileMessage).

VFile#info(reason[, position][, origin])

Like VFile#message(), but associates an informational message where fatal is set to null.

Returns

Message (VFileMessage).

VFile#fail(reason[, position][, origin])

Like VFile#message(), but associates a fatal message where fatal is set to true, and then immediately throws it.

👉 Note: a fatal error means that a file is no longer processable.

Throws

Message (VFileMessage).

Well-known fields

The following fields are considered “non-standard”, but they are allowed, and some utilities use them:

• stored (boolean) — whether a file was saved to disk, used by reporters
• result (unknown) — sometimes files have a non-string, compiled, representation, which can be stored in the result field. One example is when turning markdown into React nodes. unified uses this field to store non-string results
• map (Map) — sometimes files have a source map associated with them, this should be a Map type, which is equivalent to the RawSourceMap type from the source-map module

There are also well-known fields on messages, see them in a similar section of vfile-message.

List of utilities

• convert-vinyl-to-vfile — transform from Vinyl
• to-vfile — create a file from a filepath and read and write to the file system
• vfile-find-down — find files by searching the file system downwards
• vfile-find-up — find files by searching the file system upwards
• vfile-glob — find files by glob patterns
• vfile-is — check if a file passes a test
• vfile-location — convert between positional and offset locations
• vfile-matter — parse the YAML front matter
• vfile-message — create a file message
• vfile-messages-to-vscode-diagnostics — transform file messages to VS Code diagnostics
• vfile-mkdirp — make sure the directory of a file exists on the file system
• vfile-rename — rename the path parts of a file
• vfile-sort — sort messages by line/column
• vfile-statistics — count messages per category: failures, warnings, etc
• vfile-to-eslint — convert to ESLint formatter compatible output

👉 Note: see unist for projects that work with nodes.

Reporters

• vfile-reporter — create a report
• vfile-reporter-json — create a JSON report
• vfile-reporter-folder-json — create a JSON representation of vfiles
• vfile-reporter-pretty — create a pretty report
• vfile-reporter-junit — create a jUnit report
• vfile-reporter-position — create a report with content excerpts

👉 Note: want to make your own reporter? Reporters must accept Array<VFile> as their first argument, and return string. Reporters may accept other values too, in which case it’s suggested to stick to vfile-reporters interface.

Types

This package is fully typed with TypeScript. It exports the following additional types:

• BufferEncoding — thing that can be given as x in file.toString(x)
• Compatible — everything that can be passed as x in new VFile(x)
• Data — thing at file.data
• DataMap — interface you can add things to, to type your extensions of file.data
• Map — source map interface as supported at file.map
• Options — the fields that can be passed as options to new VFile(x)
• Reporter — a reporter
• ReporterSettings — the fields that can be passed to a reporter
• Value — valid value
• VFile — class of file itself

DataMap can be augmented to include your extensions to it:

declare module 'vfile' {
  interface DataMap {
    // `file.data.name` is typed as `string`.
    name: string
  }
}

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.

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.

Sponsor

Support this effort and give back by sponsoring on OpenCollective!

Vercel	Motif	HashiCorp	GitBook	Gatsby
Netlify	Coinbase	ThemeIsle	Expo	Boost Note	Holloway
You?

Acknowledgments

The initial release of this project was authored by @wooorm.

Thanks to @contra, @phated, and others for their work on Vinyl, which was a huge inspiration.

Thanks to @brendo, @shinnn, @KyleAMathews, @sindresorhus, and @denysdovhan for contributing commits since!

License

MIT © Titus Wormer