Introduction to Gray-Matter

Gray-Matter is a powerful library used for parsing and stringifying front matter, a form of meta-data for files. By analyzing the front matter, users can leverage the stored metadata in their applications efficiently.

Basic Usage

The primary function of Gray-Matter is to parse front matter from strings. Here’s a simple example:

 const matter = require('gray-matter'); const file = matter('---\ntitle: Blog Post\n---\nContent of the blog post.'); console.log(file); // Outputs: // {data: { title: 'Blog Post' }, content: 'Content of the blog post.', ...} 

Supported Formats

• YAML: Default format.
• JSON: Can be configured using options.
• TOML: Supported out of the box.

YAML Front Matter

Here’s an example of parsing YAML front matter:

 const yamlString = '---\ntitle: YAML Example\ndescription: A brief YAML example\n---\nSome content here.'; const parsed = matter(yamlString); console.log(parsed.data); // Outputs: // { title: 'YAML Example', description: 'A brief YAML example' } 

JSON Front Matter

To parse JSON front matter:

 const jsonString = ';;;\n{"title": "JSON Example", "published": true}\n;;;\nMore content here.'; const parsedJson = matter(jsonString, { delimiter: ';;;' }); console.log(parsedJson.data); // Outputs: // { title: 'JSON Example', published: true } 

TOML Front Matter

Parsing TOML front matter looks like this:

 const tomlString = '+++\ntitle = "TOML Example"\n+++\nContent follows.'; const parsedToml = matter(tomlString); console.log(parsedToml.data); // Outputs: // { title: 'TOML Example' } 

Stringifying Content

Converting metadata and content back to string with front matter is straightforward:

 const content = matter.stringify('Some content.', { title: 'New Post', author: 'John Doe' }); console.log(content); // Outputs: // --- // title: New Post // author: John Doe // --- // Some content. 

Usage in an Application

Below is an example of a simple Node.js application using Gray-Matter:

 const fs = require('fs'); const matter = require('gray-matter');
// Read a markdown file fs.readFile('example.md', 'utf8', (err, data) => {
  if (err) throw err;
  
  // Parse the file
  const file = matter(data);

  // Display the parsed data
  console.log(file.data); // Metadata
  console.log(file.content); // Content
});