No value

A template shows or uses a value that doesn’t exist. It may be a field the page doesn’t set, a setting that isn’t in statac.yaml, a file or value that isn’t in data/, or a value that was written empty. The message says which, and names the page or file.

What you’ll see

error  No value: `page.summary` isn't set on `content/post-1.md`
  Write `page.summary | default("")` to show nothing where it isn't set.
  More: https://statac.dev/e/no-value/

In the terminal, the message also shows the file and line, if there is one, and marks the exact text.

Why Statac stops

On a published page, a missing value comes out as nothing, or as a word such as none, and the page looks finished when it isn’t. Statac stops instead, so that you decide what a page without the value shows.

The same applies to a value that may be missing inside a list or map that the template writes itself, such as [page.summary, page.title]. Nothing would show that the value was missing, so Statac asks for a default as soon as it reads the template.

How to fix it

If every page should have the value, add it to the page the message names. If some pages don’t have it, say what they show instead:

• {{ page.summary | default("") }} shows nothing.
• {% if page.summary %}...{% endif %} leaves out the text around it as well.
• {{ page.description | default(page.summary) | default("") }} shows the description, or else the summary, or else nothing. If you leave out the last default, the message names page.summary, the last value in the chain, which was missing.

A filter that groups or collects pages by a field, such as groupby("rank"), unique(attribute="rank") or map(attribute="rank"), needs that field on every page it is given, because where to put a page without it would be a guess. The message names the page that doesn’t have the field. Leave out the pages without it first, as in site.pages | selectattr("rank", "defined") | groupby("rank"), or give map a default=. A filter that only tests a field, such as selectattr("rank", "eq", 1), skips a page without it, as if does. sort(attribute="rank") puts pages without the field last, and warns.

A page that Statac makes for a list, such as a tag’s page, has no title. For such a page, {{ headline(page) }} shows the list’s name. For any other page, it shows the page’s title if it has one.

In a snippet, page is the page being built, not a page that the call passed to the snippet. If a call passes a post to a snippet as post, the snippet reads the post’s fields as post.summary and so on.

Example

In templates/post.html:

<p>{{ page.summary }}</p>

On pages without a summary: line, leave the paragraph out:

{% if page.summary %}
<p>{{ page.summary }}</p>
{% endif %}

Its name

Name	no-value
In the terminal	statac explain no-value
To stop showing it	It stops the build, so it can't be quietened.