Jekyll - split content up into two columns - ruby

Question

I have a basic layout page template:
---
layout: default
---
<header class="sidebar">
{{ page.title }}
</header>
<section class="content">
{{ content }}
</section>
My pages that use this as the page template are just Markdown that gets put into the <section> block.
I'm looking for a way to keep all my page content in one file but have it so I can define separate content that gets put into the <header> tag from the page template.
Is there any way to do this and keep all the page's content in one file?

Answer 1

You can do so by defining the content you wish to be separate and reused in the _includes/ directory.
You would then include it by calling for example: {% include file.ext %} to include the of the file name _includes/file.ext (almost as if you just copy and pasted it in).
See section pertaining to the _includes in the Jekyll documentation here.

Answer 2

The YAML Front Matter can be used to directly store additional content for the page. This is done by creating custom key/value variables. The layout/template uses liquid tags to check to see if the secondary content is available. If so, it gets output. Otherwise, the section is skipped.
Here's an example of a layout template that checks to see if a custom variable called myvar1 is set:
---
layout: default
---
<header class="sidebar">
<h2>{{ page.title }}</h2>
{% if page.myvar1 %}
<p>Secondary content here: {{ page.myvar1 }}</p>
{% endif %}
</header>
<section class="content">
{{ content }}
</section>
Note: To match your original example, this layout file calls a parent "default" layout. For this example, the above is in a layout file called "_layouts/nested_layout.html".
To use the new slot, a myvar1 variable is added to the front matter, like this:
---
layout: nested_layout
title: This is the post test layout
myvar1: More here <strong>including bold text</strong>.
---
And here is the page content: The quick brown fox jumps over the lazy dog.
When that page is processed, the secondary content will show up. If you create another page that doesn't have myvar1, nothing will be rendered at that part of the template.
You can add as many custom variables to your pages as necessary. The values can include HTML as shown in this example. (It works for me in Jekyll 0.11.2.) If you have a lot of code that you want to add (instead of something that easily fits on one line), or if you want to have the same content available to turn on/off for multiple pages, you can use the custom variable as a flag. Then, in the {% if %} tag, you would call an include if the value is set.