Loop over every page

A template loops over a list of the whole site’s pages, such as site.pages or site.posts, and so many pages are built with it that the build went through pages by the million. The message says which list, and how many pages ran the loop.

What you’ll see

note  Loop over every page: `site.pages` is gone through on 11,243 pages
  Write `site.pages | selectattr("menu")` to choose the pages once for the site.
  More: https://statac.dev/e/loop-over-every-page/

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

Why Statac says so

Nothing is built wrongly. A loop over every page, run on every page, does work that grows with the square of the site: twice the pages take four times as long. On a small site that is too little to notice, and Statac says nothing. It says so once the pages running one loop go through five million pages between them in one build, which a site of about 2,000 pages reaches, because from there the loop is most of the time a build takes.

A filter is different. Statac works out site.pages | selectattr("menu") once for the whole site and gives every page the answer, however many pages ask.

How to fix it

Choose the pages with a filter in place of an if, so the loop runs only over the pages it shows:

{% for entry in site.pages | selectattr("menu") %}

selectattr, rejectattr, tagged, in, where, sort and newest_first are each worked out once for the site, and so is one after another. To show a few pages, take them from the list, as site.posts[:5] does; Statac then reads only those.

Some loops have to look at every page, such as one that finds a page’s place among all the posts. If the loop is on one page, such as a page that lists everything, nothing needs to change. If it is on every page and you would rather keep it, quieten the note in statac.yaml:

quiet: [loop-over-every-page]

Example

In templates/base.html, a menu of the pages that ask to be in it:

{% for entry in site.pages if entry.menu %}
<li><a href="{{ entry.url }}">{{ entry.title }}</a></li>
{% endfor %}

Every page of the site is built with this layout, and each one looks at every page to find the few for the menu. Written with a filter, the pages are chosen once:

{% for entry in site.pages | selectattr("menu") %}
<li><a href="{{ entry.url }}">{{ entry.title }}</a></li>
{% endfor %}

Its name

Name	loop-over-every-page
In the terminal	statac explain loop-over-every-page
To stop showing it	quiet: [loop-over-every-page] in statac.yaml, once you have understood it. Statac still counts it.