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

• 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

vfile is part of the unified collective.

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

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.

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.

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>

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'
  }
]

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

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.

• options (Compatible, optional) — file value

New instance (VFile).

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'}})

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

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.

List of file paths the file moved between (Array<string>).

The first is the original path and the last is the current path.

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

Raw value (Uint8Array, string, undefined).

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).

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

Cannot be set if there’s no path yet.

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.

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.

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.

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.

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

Nothing (never).

Message (VFileMessage).

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.

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

Message (VFileMessage).

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.

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

Message (VFileMessage).

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.

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

Serialized file (string).

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

type Compatible = Options | URL | VFile | Value

Custom info (TypeScript type).

Known attributes can be added to DataMap.

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

interface DataMap {}

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

Raw source map (TypeScript type).

See source-map.

• 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

Options to create messages (TypeScript type).

See Options in vfile-message.

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

• 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)

Type for a reporter (TypeScript type).

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

Configuration for reporters (TypeScript type).

type ReporterSettings = Record<string, unknown>

Contents of the file (TypeScript type).

Can either be text or a Uint8Array structure.

type Value = Uint8Array | string

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.

• 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.

• 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.

This package is fully typed with TypeScript. It exports the additional types Compatible, Data, DataMap, Map, MessageOptions, Options, Reporter, ReporterSettings, and Value.

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.

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.

Support this effort and give back by sponsoring on OpenCollective!

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		You?

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!

MIT © Titus Wormer