Missing frontmatter element causes

[techplex]

Given these posts

---
title: Test Post A
---

---
title: Test Post B
videoEmbeds:
  - "DrQZXoHlqQI"
---

This snippet from my template generates errors for posts that do not have a videoEmbeds element defined.

Here is the error:

Failed to render pages: render of "page" failed: "<path_to>/single.html": execute of template failed: template: _default/single.html:60:32: executing "main" at <len .Params.videoEmbeds>: error calling len: reflect: call of reflect.Value.Type on zero Value

<h4 class="f4">Videos ({{ len .Params.videoEmbeds }})</h4>

Is this the only solution? (Other than defining an empty videoEmbeds member in all my posts?

<h4 class="f4">Videos
  {{if isset .Params "videoEmbeds"}}
    ({{ len .Params.videoEmbeds }})
  {{end}}
</h4>

[nekr0z]

@techplex

Is this the only solution? (Other than defining an empty videoEmbeds member in all my posts?

Well, basically yes — at least for now.

It is very much rooted in the way Go templates work; the general rule of Go templates is that you can’t simply pass a nil (be it a slice, a string, a map, or whatever) to a template or a function and expect it to fail gracefully (unless it’s a with or some other function specifically designed to deal with possibly nil values).

[davidsneighbour]

@techplex

{{ len .Params.videoEmbeds }}

With is your friend.

with

{{ with .Params.videoEmbeds }}{{ len . }}{{ else }}0{{ end }}