Filters and functions | Ringroad Docs

The custom filters and functions registered on the MiniJinja environment, plus built-ins you'll use.

The engine registers exactly four filters and one function on the MiniJinja environment (src/engine/mod.rs):

Kind	Name	Registered as
Filter	`money`	`env.add_filter("money", money_filter)`
Filter	`pluralize`	`env.add_filter("pluralize", pluralize_filter)`
Filter	`newlines_to_br`	`env.add_filter("newlines_to_br", newlines_to_br_filter)`
Filter	`render_text`	`env.add_filter("render_text", render_text_filter)`
Function	`render_node`	`env.add_function("render_node", render_node_filter)`

`money`

Formats an integer amount in minor units into a currency string. Optional currency argument (ISO code, default "USD").

{{ product.base_price | money }}              {# $19.99 #}
{{ 129900 | money(currency="NGN") }}          {# ₦1,299.00 #}
{{ (item.price * item.quantity) | money }}    {# math in the pipe #}

Behavior: derives the currency exponent and symbol from ringroad_constants::currency; groups thousands with commas; handles negatives. Alphabetic multi-char symbols (e.g. KSh) get a trailing space (a documented ponytail:, "KSh " renders KSh 1,299.00).

`pluralize`

{{ cart.item_count | pluralize(singular="item", plural="items") }}

value == 1 → singular (default "item"), else plural (default "items").

`newlines_to_br`

{{ node.settings.subtext | newlines_to_br }}

Replaces every \n with <br>.

`render_text`

Renders a merchant-entered string as a nested MiniJinja template with the current context, text settings can interpolate variables:

{{ node.settings.text | render_text }}
{# text = "Hello {{ product.name }}" → "Hello <product name>" #}

Never raises: on syntax error, missing env, or any failure the original string is returned unchanged.

`render_node(child)`

Renders a child node’s template inline with the current scope, wrapping the output in the standard rr-node-{id} editor wrapper. Used to render children inside loops where node.children_rendered can’t see the loop scope:

{% for child in node.children %}
  {{ render_node(child) }}
{% endfor %}

The theme slug is derived from the current template name.
The child’s node variable is replaced with the passed child.
Never raises: missing template or unknown type → empty string.

Built-in filters that matter

MiniJinja ships the standard Jinja2 filter set; the default theme leans on:

Filter	Usage in the default theme
`safe`	`page.content_html`, `page_styles`, `header_html`, `settings.html_head`, snippet `attrs`
`default`	`hg
`length`	`product.variants
`urlencode`	share links (`request.path
`replace` / `trim` / `lower` / `upper`	general string work
`first` / `last` / `join`	array access

Known gaps

image_url is not registered. The default theme calls {{ img.src | image_url }} in navbar.jinja, product_gallery.jinja, and product_recommendations.jinja, but no such filter exists in the engine, those render paths raise an unknown-filter error today. Either the API provides ready URLs or the filter needs registering.
No asset_url / section / block filters exist, asset paths are hardcoded (/_assets/main.css) or come pre-resolved from data.