vfile-message

What is vfile-message?

The vfile-message npm package is designed for creating and managing virtual file messages, such as warnings and errors, in a standardized format. It is commonly used in file processing pipelines to report issues found during the processing of files. These messages can include details such as the position of the issue within the file, the rule that was violated, and a human-readable message describing the problem.

What are vfile-message's main functionalities?

Creating a new message

This code demonstrates how to create a new vfile message. The message includes a human-readable string, a position object indicating where in the file the message applies, and an optional error code.

{"const VFileMessage = require('vfile-message');\nconst message = new VFileMessage('This is an error message', {line: 10, column: 5}, 'error-code');\nconsole.log(message);"}

Associating a message with a file

This example shows how to create a vfile message and associate it with a vfile. The message is pushed into the file's `messages` array, allowing multiple messages to be associated with a single file.

{"const vfile = require('vfile');\nconst VFileMessage = require('vfile-message');\nconst file = vfile();\nconst error = new VFileMessage('Invalid syntax', {line: 2, column: 10}, 'syntax-error');\nfile.messages.push(error);\nconsole.log(file.messages);"}

Other packages similar to vfile-message

eslint

ESLint is a tool for identifying and reporting on patterns found in ECMAScript/JavaScript code, making it somewhat similar to vfile-message in its ability to report errors and warnings. However, ESLint is more focused on linting JavaScript code according to customizable coding standards, whereas vfile-message is more generic and can be used with any type of file.

chalk

Chalk is a package for styling terminal text. While not directly similar to vfile-message in functionality, it is often used alongside vfile-message and other reporting tools to colorize messages (errors, warnings) for better visibility in the console. Chalk does not create or manage messages but enhances the presentation of messages created by packages like vfile-message.

remark-lint

Remark-lint is a markdown code style linter that is part of the unified.js ecosystem, similar to vfile-message which is also often used in the unified ecosystem for handling messages. Remark-lint focuses specifically on linting Markdown files according to a set of rules, generating messages (warnings, errors) similar to those created by vfile-message, but with a focus on Markdown content.

README

vfile-message

Create vfile messages.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • VFileMessage(reason[, place][, origin])
  • Well-known
• Types
• Compatibility
• Contribute
• License

What is this?

This package provides a (lint) message format.

When should I use this?

In most cases, you can use file.message from VFile itself, but in some cases you might not have a file, and still want to emit warnings or errors, in which case this can be used directly.

Install

This package is ESM only. In Node.js (version 14.14+ and 16.0+), install with npm:

npm install vfile-message

In Deno with esm.sh:

import {VFileMessage} from 'https://esm.sh/vfile-message@3'

In browsers with esm.sh:

<script type="module">
  import {VFileMessage} from 'https://esm.sh/vfile-message@3?bundle'
</script>

Use

import {VFileMessage} from 'vfile-message'

const message = new VFileMessage(
  'Unexpected unknown word `braavo`, did you mean `bravo`?',
  {line: 1, column: 8},
  'spell:typo'
)

console.log(message)

Yields:

[1:8: Unexpected unknown word `braavo`, did you mean `bravo`?] {
  reason: 'Unexpected unknown word `braavo`, did you mean `bravo`?',
  line: 1,
  column: 8,
  source: 'spell',
  ruleId: 'typo',
  position: {start: {line: 1, column: 8}, end: {line: null, column: null}}
}

API

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

VFileMessage(reason[, place][, origin])

Create a message for reason at place from origin.

When an error is passed in as reason, the stack is copied.

Parameters

• reason (string or Error) — reason for message, uses the stack and message of the error if given
• place (Node, Position, or Point, optional) — place in file where the message occurred
• origin (string, optional) — place in code where the message originates (example: 'my-package:my-rule' or 'my-rule')

Extends

Error.

Returns

Instance of VFileMessage.

Fields

• reason (string) — reason for message (you should use markdown)
• fatal (boolean | null | undefined) — state of problem; true marks associated file as no longer processable (error); false necessitates a (potential) change (warning); null | undefined for things that might not need changing (info)
• line (number | null) — starting line of error
• column (number | null) — starting column of error
• position (Position | null) — full unist position
• source (string | null, example: 'my-package') — namespace of message
• ruleId (string | null, example: 'my-rule') — category of message
• stack (string | null) — stack of message in code
• file (string | null) — path of a file (used throughout the VFile ecosystem)

Well-known

It’s OK to store custom data directly on the VFileMessage, some of those are handled by utilities. The following fields are documented and typed here.

Fields

• actual (string | null) — specify the source value that’s being reported, which is deemed incorrect
• expected (Array<string> | null) — suggest acceptable values that can be used instead of actual
• url (string | null) — link to docs for the message (this must be an absolute URL that can be passed as x to new URL(x))
• note (string | null) — long form description of the message (you should use markdown)

Types

This package is fully typed with TypeScript. It exports no additional types.

Compatibility

Projects maintained by the unified collective are compatible with all maintained versions of Node.js. As of now, that is Node.js 14.14+ and 16.0+. Our projects sometimes work with older versions, but this is not guaranteed.

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.

License

MIT © Titus Wormer