# Style for Templates

This directory has templates in the [Tera templating language](teradoc), which is very
similar to [Jinja2](jinjadoc) and [Django](djangodoc) templates, and also to [Askama](askamadoc).

[teradoc]: https://tera.netlify.app/docs/#templates
[jinjadoc]: https://jinja.palletsprojects.com/en/3.0.x/templates/
[djangodoc]: https://docs.djangoproject.com/en/3.2/topics/templates/
[askamadoc]: https://docs.rs/askama/0.10.5/askama/

We want our rendered output to have as little unnecessary whitespace as
possible, so that pages load quickly. To achieve that we use Tera's
[whitespace control] features. At the end of most lines, we put an empty comment
tag with the whitespace control characters: `{#- -#}`. This causes all
whitespace between the end of the line and the beginning of the next, including
indentation, to be omitted on render. Sometimes we want to preserve a single
space. In those cases we put the space at the end of the line, followed by
`{# -#}`, which is a directive to remove following whitespace but not preceding.
We also use the whitespace control characters in most instances of tags with
control flow, for example `{%- if foo -%}`.

[whitespace control]: https://tera.netlify.app/docs/#whitespace-control

We want our templates to be readable, so we use indentation and newlines
liberally. We indent by four spaces after opening an HTML tag _or_ a Tera
tag. In most cases an HTML tag should be followed by a newline, but if the
tag has simple contents and fits with its close tag on a single line, the
contents don't necessarily need a new line.

Tera templates support quite sophisticated control flow. To keep our templates
simple and understandable, we use only a subset: `if` and `for`. In particular
we avoid [assignments in the template logic](assignments) and [Tera
macros](macros). This also may make things easier if we switch to a different
Jinja-style template system, like Askama, in the future.

[assignments]: https://tera.netlify.app/docs/#assignments
[macros]: https://tera.netlify.app/docs/#macros
