What is YAML Front Matter?

  Aug 2, 2018
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 yaml, yml, front-matter 

Lately I started tinkering around with framework for static site generation sites, and I saw something new that I did not know. The so called YAML Front Matter (or just Front Matter).

At first the name confused me quite a lot, but after a while I realized how simple it is. Front Matter is nothing else that a space at the beginning of your templates, that is used to define variables, in YAML format. That is it. Let’s see an example with Markdown and with HTML

---
slug: about
comments_enabled: false
---

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
    </head>
<body>
    <header>
        <h1>About page</h1>
    </header>

    <main>...</main>
</body>
</html>
---
published: true
---

# My first post

Hello world

## Another section

lorem lorem lorem lorem lorem lorem 

There is not much more to it. It basically couples tightly the variables of your page, to the document itself.

There are a couple restrictions that is necessary to know, thought:

  1. The Front Matter needs to come the first thing in the document. There must not be anything in front. Not even white space.
  2. The Front Matter must be wrapped in what is called the triple dash `—`. This is not just like a comment block, or a random way to separate the YAML from the rest of the document. It must always use this three hyphens at the beginning and end of the variable list.

I hope this helps someone. Cheers!