Markdown rendered incorrectly with npm-markdown

I am using nodejs-markdown from here: https://npmjs.org/package/markdown But the stuff between "---" in the headers is not getting rendered - only horizontal lines are created

Why does this occur? Does this automatically convert the stuff into some kind of meta-data?

---
layout: post    
title: Just another post
something: more
this
and that
and more of that
---

About Me
--------
I'm a programmer 

I am using nodejs-markdown from here: https://npmjs.org/package/markdown But the stuff between "---" in the headers is not getting rendered - only horizontal lines are created

Why does this occur? Does this automatically convert the stuff into some kind of meta-data?

EDIT: Input to npm-Markdown is:

var content = fs.readFileSync(filepath,'utf8');
var htmlContent = markdown.toHTML(content);

Output is as shown below - with nothing rendered between the hr's:

<hr/>
<hr/>
<h2>About Me</h2>
<p>I&#39;m a programmer</p>