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 retext (natural language) and mdast (markdown). Two processors which parse, transform, and compile text. Both need a virtual representation of files and a place to store metadata and messages. And, they work in the browser. VFile provides these requirements.

Also, VFile exposes a warning mechanism compatible with ESLints formatters, making it easy to expose stylish warnings, or export tap compliant messages.

VFile is different from (the excellent :+1:) vinyl in that it does not include file-system or node-only functionality. No buffers, streams, or stats. In addition, the focus on metadata and messages are useful when processing a file through a middleware pipeline.

Installation

npm:

npm install vfile

VFile is also available for bower, component, and duo, and as an AMD, CommonJS, and globals module, uncompressed and compressed.

Table of Contents

• Usage

• Related Tools

• API

  • VFile()
  • VFile#contents
  • VFile#directory
  • VFile#filename
  • VFile#extension
  • VFile#quiet
  • VFile#messages
  • VFile#history
  • VFile#toString()
  • VFile#filePath()
  • VFile#move(options)
  • VFile#namespace(key)
  • VFile#message(reason, position?)
  • VFile#warn(reason, position?)
  • VFile#fail(reason, position?)
  • VFile#hasFailed()
  • VFileMessage

• License

Usage

var VFile = require('vfile');

var file = new VFile({
  'directory': '~',
  'filename': 'example',
  'extension': 'txt',
  'contents': 'Foo *bar* baz'
});

file.toString(); // 'Foo *bar* baz'
file.filePath(); // '~/example.txt'

file.move({'extension': 'md'});
file.filePath(); // '~/example.md'

file.warn('Something went wrong', {'line': 1, 'column': 3});
// { [~/example.md:1:3: Something went wrong]
//   name: '~/example.md:1:3',
//   file: '~/example.md',
//   reason: 'Something went wrong',
//   line: 1,
//   column: 3,
//   fatal: false }

Related Tools

VFiles are used by both retext and mdast.

In addition, here’s a list of useful tools:

• wooorm/to-vfile — Create a virtual file from a file-path;

• wooorm/vfile-sort — Sort virtual file messages by line/column;

• wooorm/vfile-reporter — Stylish reporter for virtual files.

API

VFile()

VFile objects make it easy to move files, to trigger warnings and errors, and to store supplementary metadata relating to files, all without accessing the file-system.

Example

var file = new VFile({
  'directory': '~',
  'filename': 'example',
  'extension': 'txt',
  'contents': 'Foo *bar* baz'
});

file === VFile(file); // true
file === new VFile(file); // true

VFile('foo') instanceof VFile; // true

Signatures

• file = VFile(contents|options|vFile?).

Parameters

• contents (string) — Contents of the file;

• vFile (VFile) — Existing representation, returned without modification;

• options (Object):

  • directory (string?, default: '') — Parent directory;

  • filename (string?, default: '') — Name, without extension;

  • extension (string?, default: '') — Extension(s), without initial dot;

  • contents (string?, default: '') — Raw value.

Returns

vFile — Instance.

Notes

VFile exposes an interface compatible with ESLint’s formatters. For example, to expose warnings using ESLint’s compact formatter, execute the following:

var compact = require('eslint/lib/formatters/compact');
var VFile = require('vfile');

var vFile = new VFile({
    'directory': '~',
    'filename': 'hello',
    'extension': 'txt'
});

vFile.warn('Whoops, something happened!');

console.log(compact([vFile]));

Which would yield the following:

~/hello.txt: line 0, col 0, Warning - Whoops, something happened!

1 problem

VFile#contents

string — Content of file.

VFile#directory

string — Path to parent directory.

VFile#filename

string — Filename. A file-path can still be generated when no filename exists.

VFile#extension

string — Extension. A file-path can still be generated when no extension exists.

VFile#quiet

boolean? — Whether an error created by VFile#fail() is returned (when truthy) or thrown (when falsey).

Ensure all messages associated with a file are handled properly when setting this to true.

VFile#messages

Array.<VFileMessage> — List of associated messages.

Notes

VFile#message(), and in turn VFile#warn() and VFile#fail(), return Error objects that adhere to the VFileMessage schema. Its results can populate messages.

VFile#history

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

VFile#toString()

Get the value of the file.

Example

var vFile = new VFile('Foo');
String(vFile); // 'Foo'

Signatures

• string = vFile.toString().

Returns

string — Contents.

VFile#filePath()

Get the filename, with extension and directory, if applicable.

Example

var file = new VFile({
  'directory': '~',
  'filename': 'example',
  'extension': 'txt'
});

String(file.filePath); // ~/example.txt
file.filePath() // ~/example.txt

Signatures

• string = vFile.filePath().

Returns

string — If the vFile has a filename, it will be prefixed with the directory (slashed), if applicable, and suffixed with the (dotted) extension (if applicable). Otherwise, an empty string is returned.

VFile#move(options)

Move a file by passing a new directory, filename, and extension. When these are not given, the default values are kept.

Example

var file = new VFile({
  'directory': '~',
  'filename': 'example',
  'extension': 'txt',
  'contents': 'Foo *bar* baz'
});

file.move({'directory': '/var/www'});
file.filePath(); // '/var/www/example.txt'

file.move({'extension': 'md'});
file.filePath(); // '/var/www/example.md'

Signatures

• vFile = vFile.move(options?).

Parameters

• options (Object):

  • directory (string, default: '') — Parent directory;

  • filename (string?, default: '') — Name, without extension;

  • extension (string, default: '') — Extension(s), without initial dot.

Returns

vFile — Context object (chainable).

VFile#namespace(key)

Access metadata.

Example

var file = new VFile('Foo');

file.namespace('foo').bar = 'baz';

console.log(file.namespace('foo').bar) // 'baz';

Parameters

• key (string) — Namespace key.

Returns

Object — Private namespace for metadata.

VFile#message(reason, position?)

Create a message with reason at position. When an error is passed in as reason, copies the stack. This does not add a message to messages.

Example

var file = new VFile();

file.message('Something went wrong');
// { [1:1: Something went wrong]
//   name: '1:1',
//   file: '',
//   reason: 'Something went wrong',
//   line: null,
//   column: null }

Signatures

• VFileMessage = vFile.message(err|reason, node|location|position?).

Parameters

• err (Error) — Original error, whose stack and message are used;

• reason (string) — Reason for message;

• node (Node) — Syntax tree object;

• location (Object) — Syntax tree location (found at node.position);

• position (Object) — Syntax tree position (found at node.position.start or node.position.end).

Returns

VFileMessage — File-related message with location information.

VFile#warn(reason, position?)

Warn. Creates a non-fatal message (see VFile#message()), and adds it to the file's messages list.

Example

var file = new VFile();

file.warn('Something went wrong');
// { [1:1: Something went wrong]
//   name: '1:1',
//   file: '',
//   reason: 'Something went wrong',
//   line: null,
//   column: null,
//   fatal: false }

See

• VFile#message

VFile#fail(reason, position?)

Fail. Creates a fatal message (see VFile#message()), sets fatal: true, adds it to the file's messages list.

If quiet is not true, throws the error.

Example

var file = new VFile();

file.fail('Something went wrong');
// 1:1: Something went wrong
//     at VFile.exception (vfile/index.js:296:11)
//     at VFile.fail (vfile/index.js:360:20)
//     at repl:1:6

file.quiet = true;
file.fail('Something went wrong');
// { [1:1: Something went wrong]
//   name: '1:1',
//   file: '',
//   reason: 'Something went wrong',
//   line: null,
//   column: null,
//   fatal: true }

See

• VFile#message

VFile#hasFailed()

Check if a fatal message occurred making the file no longer processable.

Example

var file = new VFile();
file.quiet = true;

file.hasFailed(); // false

file.fail('Something went wrong');
file.hasFailed(); // true

Signatures

• boolean = vFile.hasFailed().

Returns

boolean — true if at least one of file’s messages has a fatal property set to true.

VFileMessage

Error — File-related message with location information.

Properties

• name (string) — (Starting) location of the message, preceded by its file-path when available, and joined by ':'. Used by the native Error#toString();

• file (string) — File-path;

• reason (string) — Reason for message;

• line (number?) — Line of error, when available;

• column (number?) — Column of error, when available;

• stack (string?) — Stack of message, when available;

• fatal (boolean?) — Whether the associated file is still processable.

• 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