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.cwd
  • file.data
  • file.history
  • file.messages
  • file.value
  • file.basename
  • file.dirname
  • file.extname
  • file.path
  • file.stem
  • VFile#fail(reason[, options])
  • VFile#info(reason[, options])
  • VFile#message(reason[, options])
  • VFile#toString(encoding?)
  • Compatible
  • Data
  • DataMap
  • Map
  • MessageOptions
  • Options
  • Reporter
  • ReporterSettings
  • Value
  • Well-known
• 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 16+), install with npm:

npm install vfile

In Deno with esm.sh:

import {VFile} from 'https://esm.sh/vfile@6'

In browsers with esm.sh:

<script type="module">
  import {VFile} from 'https://esm.sh/vfile@6?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`?', {
  place: {line: 1, column: 8},
  source: 'spell',
  ruleId: 'typo'
})

console.log(file.messages)

Yields:

[
  [~/index.text:1:8: Unexpected unknown word `braavo`, did you mean `bravo`?] {
    ancestors: undefined,
    cause: undefined,
    column: 8,
    fatal: false,
    line: 1,
    place: { line: 1, column: 8 },
    reason: 'Unexpected unknown word `braavo`, did you mean `bravo`?',
    ruleId: 'typo',
    source: 'spell',
    file: '~/index.text'
  }
]

API

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

VFile(options?)

Create a new virtual file.

options is treated as:

• string or Uint8Array — {value: options}
• URL — {path: options}
• VFile — shallow copies its data over to the new file
• object — all fields are shallow copied over to the new file

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

You cannot set dirname or extname without setting either history, path, basename, or stem too.

Parameters

• options (Compatible, optional) — file value

Returns

New instance (VFile).

Example

new VFile()
new VFile('console.log("alpha");')
new VFile(new Uint8Array([0x65, 0x78, 0x69, 0x74, 0x20, 0x31]))
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.cwd

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

file.data

Place to store custom info (Record<string, unknown>, default: {}).

It’s OK to store custom data directly on the file but moving it to data is recommended.

file.history

List of file paths 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.value

Raw value (Uint8Array, string, undefined).

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.dirname

Get or set the parent path (string?, example: '~').

Cannot be set if there’s no path yet.

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.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.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.

VFile#fail(reason[, options])

Create a fatal message for reason associated with the file.

The fatal field of the message is set to true (error; file not usable) and the file field is set to the current file path. The message is added to the messages field on file.

🪦 Note: also has obsolete signatures.

Parameters

• reason (string) — reason for message, should use markdown
• options (MessageOptions, optional) — configuration

Returns

Nothing (never).

Throws

Message (VFileMessage).

VFile#info(reason[, options])

Create an info message for reason associated with the file.

The fatal field of the message is set to undefined (info; change likely not needed) and the file field is set to the current file path. The message is added to the messages field on file.

🪦 Note: also has obsolete signatures.

Parameters

• reason (string) — reason for message, should use markdown
• options (MessageOptions, optional) — configuration

Returns

Message (VFileMessage).

VFile#message(reason[, options])

Create a message for reason associated with the file.

The fatal field of the message is set to false (warning; change may be needed) and the file field is set to the current file path. The message is added to the messages field on file.

🪦 Note: also has obsolete signatures.

Parameters

• reason (string) — reason for message, should use markdown
• options (MessageOptions, optional) — configuration

Returns

Message (VFileMessage).

VFile#toString(encoding?)

Serialize the file.

Note: which encodings are supported depends on the engine. For info on Node.js, see: https://nodejs.org/api/util.html#whatwg-supported-encodings.

Parameters

• encoding (string, default: 'utf8') — character encoding to understand value as when it’s a Uint8Array

Returns

Serialized file (string).

Compatible

Things that can be passed to the constructor (TypeScript type).

Type

type Compatible = Options | URL | VFile | Value

Data

Custom info (TypeScript type).

Known attributes can be added to DataMap.

Type

type Data = Record<string, unknown> & Partial<DataMap>

DataMap

This map registers the type of the data key of a VFile (TypeScript type).

This type can be augmented to register custom data types.

Type

interface DataMap {}

Example

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

Map

Raw source map (TypeScript type).

See source-map.

Fields

• version (number) — which version of the source map spec this map is following
• sources (Array<string>) — an array of URLs to the original source files
• names (Array<string>) — an array of identifiers which can be referenced by individual mappings
• sourceRoot (string, optional) — the URL root from which all sources are relative
• sourcesContent (Array<string>, optional) — an array of contents of the original source files
• mappings (string) — a string of base64 VLQs which contain the actual mappings
• file (string) — the generated file this source map is associated with

MessageOptions

Options to create messages (TypeScript type).

See Options in vfile-message.

Options

An object with arbitrary fields and the following known fields (TypeScript type).

Fields

• basename (string, optional) — set basename (name)
• cwd (string, optional) — set cwd (working directory)
• data (Data, optional) — set data (associated info)
• dirname (string, optional) — set dirname (path w/o basename)
• extname (string, optional) — set extname (extension with dot)
• history (Array<string>, optional) — set history (paths the file moved between)
• path (URL | string, optional) — set path (current path)
• stem (string, optional) — set stem (name without extension)
• value (Value, optional) — set value (the contents of the file)

Reporter

Type for a reporter (TypeScript type).

Type

type Reporter<Settings = ReporterSettings> = (
  files: Array<VFile>,
  options: Settings
) => string

ReporterSettings

Configuration for reporters (TypeScript type).

Type

type ReporterSettings = Record<string, unknown>

Value

Contents of the file (TypeScript type).

Can either be text or a Uint8Array structure.

Type

type Value = Uint8Array | string

Well-known

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

• map (Map) — source map; this type is equivalent to the RawSourceMap type from the source-map module
• result (unknown) — custom, non-string, compiled, representation; this is used by unified to store non-string results; one example is when turning markdown into React nodes
• stored (boolean) — whether a file was saved to disk; this is used by vfile reporters

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 file path 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 additional types Compatible, Data, DataMap, Map, MessageOptions, Options, Reporter, ReporterSettings, and Value.

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@^6, 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.

Sponsor

Support this effort and give back by sponsoring on OpenCollective!

Vercel	Motif	HashiCorp	GitBook	Gatsby
Netlify	Coinbase	ThemeIsle	Expo	Boost Note	Markdown Space	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