front-matter

What is front-matter?

The front-matter npm package is used to parse YAML or JSON front matter from strings, typically used in markdown files. This is useful for extracting metadata from content files.

What are front-matter's main functionalities?

Parsing Front Matter

This feature allows you to parse a string containing front matter and extract the metadata and content separately.

const frontMatter = require('front-matter');
const content = '---\ntitle: Hello World\ndate: 2023-10-01\n---\nThis is the content of the file.';
const parsed = frontMatter(content);
console.log(parsed.attributes); // { title: 'Hello World', date: '2023-10-01' }
console.log(parsed.body); // 'This is the content of the file.'

Custom Delimiters

This feature allows you to specify custom delimiters for the front matter, which is useful if your front matter is not delimited by the default '---'.

const frontMatter = require('front-matter');
const content = '+++\ntitle: Hello World\ndate: 2023-10-01\n+++\nThis is the content of the file.';
const options = { delimiters: '+++' };
const parsed = frontMatter(content, options);
console.log(parsed.attributes); // { title: 'Hello World', date: '2023-10-01' }
console.log(parsed.body); // 'This is the content of the file.'

Other packages similar to front-matter

gray-matter

gray-matter is a popular package for parsing front matter from strings. It supports YAML, JSON, and TOML front matter, and offers more features like custom engines and stringifying parsed data back to front matter format. It is more feature-rich compared to front-matter.

README

front-matter

Extract meta data (front-matter) from documents.

This modules does not do any IO (file loading or reading), only extracting and parsing front matter from strings.

This concept that was originally introduced to me through the jekyll blogging system and is pretty useful where you want to be able to easily add meta-data to content without the need for a database. YAML is extracted from the the top of a file between matching separators of "---" or "= yaml =". It will also extract YAML between a separator and "...".

Install

With npm do:

npm install front-matter

Example

So you have a file example.md:

---
title: Just hack'n
description: Nothing to see here
---

This is some text about some stuff that happened sometime ago

NOTE: As of front-matter@2.0.0 valid front matter is considered to have the starting separator on the first line.

Then you can do this:

var fs = require('fs')
  , fm = require('front-matter')

fs.readFile('./example.md', 'utf8', function(err, data){
  if (err) throw err

  var content = fm(data)

  console.log(content)
})

And end up with an object like this:

{
    attributes: {
        title: 'Just hack\'n',
        description: 'Nothing to see here'
    },
    body: 'This is some text about some stuff that happened sometime ago',
    bodyBegin: 6,
    frontmatter: 'title: Just hack\'n\ndescription: Nothing to see here'
}

Methods

var fm = require('front-matter')

fm(string, { allowUnsafe: false })

Return a content object with two properties:

• content.attributes contains the extracted yaml attributes in json form
• content.body contains the string contents below the yaml separators
• content.bodyBegin contains the line number the body contents begins at
• content.frontmatter contains the original yaml string contents

NOTE: By default fm() uses ys-yaml's safeLoad unless you set allowUnsafe in the options object to true.

fm.test(string)

Check if a string contains a front matter header of "---" or "= yaml =". Primarily used internally but is useful outside of the module.

Returns true or false

    fm.test(string) #=> true || false

Contributing

front-matter is an OPEN Source Project so please help out by reporting bugs or forking and opening pull requests when possible.

All code is linted/formatted using standard style, any non-conforming code can be automatically formatted using the the fmt make task: make fmt.

Maintainers

• Adrian Gimenez
• Jason Campbell - @jxson

Contributors

This module is awesome because of all the folks who submitted pull requests:

• Jordan Santell - @jsantell
• Jean-Philippe Monette - @jpmonette
• Kai Davenport
• Marc-André Arseneault - @im_arsnl
• Bret Comnes - http://bret.io
• Shinnosuke Watanabe
• Matt Dickens
• Rod Knowlton
• Rich DeLauder
• Sean Lang - http://slang.cx
• Benjamin Tan - https://d10.github.io/
• Kenneth Lim - https://kenlimmj.com
• Cameron Moy
• Fernando Montoya - https://montogeek.com
• Martin Heidegger
• Leo Liang
• Kasper Pedersen

CHANGELOG

3.0.0

• CI only tests Node versions >= v6 (drops v4, and v5)

LICENSE (MIT)

Copyright (c) Jason Campbell ("Author")

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.