Liquid + Jekyll, "unless" not working inside "for" loop - jekyll

Question

I'm making JSON given a set of pages. I want to skip any pages without titles, and the last element can not have a comma after it, that's bad JSON. Tried different variations, here is an example:
---
---
[
{% for page in site.pages %}
{% unless page.title %}
{% continue %}
{% else %}
{
"title":"{{ page.title }}",
"content":"{{ page.content | strip_html | strip_newlines }}",
"href":"{{ page.url }}"
}
{% endunless %}
{% unless forloop.last %},{% endunless %}
{% endfor %}
]
The end of the resulting JSON file looks like this:
{
"title":"Test Search",
"content":" ",
"href":"/search.html"
}
,
]
How do I get rid of the trailing comma? Thank you in advance.

Answer 1

I think your problem is that your last loop iteration is one that has no title.
Try to prepend the comma. That way you don't have to look in the future:
{% assign isFirst = true %}
{% for page in site.pages %}
{% unless page.title %}{% continue %}{% endunless %}
{% unless isFirst %},{% endunless %}
{% assign isFirst = false %}
{
"title": {{ page.title | jsonify }},
"content": {{ page.content | strip_html | strip_newlines | jsonify }},
"href": {{ page.url | jsonify }}
}
{% endfor %}
Edit: You should also use the jsonify filter to ensure proper escaping of quotes and other characters.

Answer 2

Try using {% raw %} to escape your non-liquid brackets, this can cause Jekyll to misbehave without throwing any errors.
If that still leads to odd behavior try creating a seperate array like the following example, which is very similar to the case from OP.
{% assign suggestions = "" | split: ',' %}
{%- for item in site[page.collection] -%}
{%- unless item.url == page.url -%}
{% assign suggestions = suggestions | push: item %}
{%- endunless -%}
{%- endfor -%}
<script id="suggest-json" type="application/json">
[
{%- for item in suggestions -%}
{% assign images = item.media | where: "type", "image" %}
{% assign image = images.first %}
{% raw %}
{
{% endraw %}
"url": "{{ site.baseurl }}{{ item.url }}",
"title": {{ item.title | jsonify }},
"subject": {{ item.game | jsonify }},
"image": {{ image.thumbnail | jsonify }},
"alt": {{ image.thumbnail_alt | jsonify }}
{% raw %}
}
{% endraw %}
{%- unless forloop.last -%},{%- endunless -%}
{%- endfor -%}
]
</script>
The problem may be that Jekyll doesn't actually consider the forloop.index as last because it isn't technically. You can avoid this by creating a new array either with a loop or the 'where' tag (loop used above).
The forloop.last should now behave properly, hope this helps.