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 virtual file format used by unified, a text processing umbrella (it powers retext for natural language, remark for markdown, and rehype for HTML). Each processors that parse, transform, and compile text, and need a virtual representation of files and a place to store messages about them. Plus, they work in the browser. VFile provides these requirements at a small size, in IE 9 and up.

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

Installation

npm:

npm install vfile

Table of Contents

• Usage
• Utilities
• Reporters
• API
  • VFile([options])
  • vfile.contents
  • vfile.cwd
  • vfile.path
  • vfile.basename
  • vfile.stem
  • vfile.extname
  • vfile.dirname
  • vfile.history
  • vfile.messages
  • vfile.data
  • VFile#toString([encoding])
  • VFile#message(reason[, position[, ruleId]])
  • VFile#info(reason[, position[, ruleId]])
  • VFile#fail(reason[, position[, ruleId]])
  • VFileMessage
• License

Usage

var vfile = require('vfile');

var file = vfile({path: '~/example.txt', contents: 'Alpha *braavo* charlie.'});

file.path; //=> '~/example.txt'
file.dirname; //=> '~'

file.extname = '.md';

file.basename; //=> 'example.md'

file.basename = 'index.text';

file.history; //=> ['~/example.txt', '~/example.md', '~/index.text']

file.message('`braavo` is misspelt; did you mean `bravo`?', {line: 1, column: 8});

console.log(file.messages);

Yields:

[ { [~/index.text:1:8: `braavo` is misspelt; did you mean `bravo`?]
    message: '`braavo` is misspelt; did you mean `bravo`?',
    name: '~/index.text:1:8',
    file: '~/index.text',
    reason: '`braavo` is misspelt; did you mean `bravo`?',
    line: 1,
    column: 8,
    location: { start: [Object], end: [Object] },
    ruleId: null,
    source: null,
    fatal: false } ]

Utilities

The following list of projects includes tools for working with virtual files. See Unist for projects working with nodes.

• convert-vinyl-to-vfile — Convert from Vinyl
• is-vfile-message — Check if a value is a VFileMessage object
• to-vfile — Create a virtual file from a file-path (and optionally read it)
• vfile-find-down — Find files by searching the file system downwards
• vfile-find-up — Find files by searching the file system upwards
• vfile-location — Convert between line/column- and range-based locations
• vfile-statistics — Count messages per category
• vfile-messages-to-vscode-diagnostics — Convert to VS Code diagnostics
• vfile-sort — Sort messages by line/column
• vfile-to-eslint — Convert VFiles to ESLint formatter compatible output

Reporters

The following list of projects show linting results for given virtual files. 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.

• vfile-reporter — Stylish reporter
• vfile-reporter-json — JSON reporter
• vfile-reporter-pretty — Pretty reporter

API

VFile([options])

Create a new virtual file. If options is string or Buffer, treats it as {contents: options}. If options is a VFile, returns it. All other options are set on the newly created vfile.

Path related properties 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

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

vfile.contents

Buffer, string, null — Raw value.

vfile.cwd

string — Base of path. Defaults to process.cwd().

vfile.path

string? — Path of vfile. Cannot be nullified.

vfile.basename

string? — Current name (including extension) of vfile. Cannot contain path separators. Cannot be nullified either (use file.path = file.dirname instead).

vfile.stem

string? — Name (without extension) of vfile. Cannot be nullified, and cannot contain path separators.

vfile.extname

string? — Extension (with dot) of vfile. Cannot be set if there’s no path yet and cannot contain path separators.

vfile.dirname

string? — Path to parent directory of vfile. Cannot be set if there’s no path yet.

vfile.history

Array.<string> — List of file-paths the file moved between.

vfile.messages

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

vfile.data

Object — Place to store custom information. It’s OK to store custom data directly on the vfile, moving it to data gives a little more privacy.

VFile#toString([encoding])

Convert contents of vfile to string. If contents is a buffer, encoding is used to stringify buffers (default: 'utf8').

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

Associates a message with the file for reason at position. When an error is passed in as reason, copies the stack. Each message has a fatal property which by default is set to false (ie. warning).

Parameters

• reason (string or Error) — Reason for message, uses the stack and message of the error if given
• position (Node, Location, or Position, optional) — Place at which the message occurred in vfile
• ruleId (string, optional) — Category of message

Returns

VFileMessage.

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

Associates an informational message with the file, where fatal is set to null. Calls #message() internally.

Returns

VFileMessage.

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

Associates a fatal message with the file, then immediately throws it. Note: fatal errors mean a file is no longer processable. Calls #message() internally.

Throws

VFileMessage.

VFileMessage

File-related message describing something at certain position (extends Error).

Properties

• file (string) — File-path (when the message was triggered)
• reason (string) — Reason for message
• ruleId (string?) — Category of message
• source (string?) — Namespace of warning
• stack (string?) — Stack of message
• fatal (boolean?) — If true, marks associated file as no longer processable
• line (number?) — Starting line of error
• column (number?) — Starting column of error
• location (object) — Full range information, when available. Has start and end properties, both set to an object with line and column, set to number?

License

MIT © Titus Wormer