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
vfile is part of the unified collective.
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 fileobject — 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
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 markdownoptions (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 markdownoptions (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 markdownoptions (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 followingsources (Array<string>) — an array of URLs to the original source filesnames (Array<string>) — an array of identifiers which can be referenced by individual mappingssourceRoot (string, optional) — the URL root from which all sources are relativesourcesContent (Array<string>, optional) — an array of contents of the original source filesmappings (string) — a string of base64 VLQs which contain the actual mappingsfile (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 moduleresult (unknown) — custom, non-string, compiled, representation; this is used by unified to store non-string results; one example is when turning markdown into React nodesstored (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
👉 Note: see unist for projects that work with nodes.
Reporters
👉 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.
Support this effort and give back by sponsoring on OpenCollective!
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