Template Engine

The templates module renders Jet templates from configured sets. Templates can use inheritance and includes. This page is an API reference with isolated rendering examples, not a standalone template deployment. The registry IDs and template sources must already be configured, and the executable entry must enable templates and have template.get permission for the requested set.

For template set configuration, see Template Engine.

Loading

local templates = require("templates")

`templates.get`

Acquire a template set by registry ID:

local set, err = templates.get("app.views:emails")
if err then
    return nil, err
end

-- Use the set...

return set:release()

Parameter	Type	Description
`id`	string	Template set registry ID

Returns: Set, error

`set:render`

Render a template by name with data:

local set, get_err = templates.get("app.views:emails")
if get_err then
    return nil, get_err
end

local html, err = set:render("welcome", {
    user = {name = "Alice", email = "alice@example.com"},
    activation_url = "https://example.invalid/activate"
})

set:release()
if err then
    return nil, err
end

return html

The caller owns every acquired set until release() is called. Release it after the final render, including checked error paths; repeated releases are safe. Rendering does not make application-provided values safe for every output context. Keep secrets and one-time URLs out of logs, and apply the escaping or sanitization required where the rendered string is consumed.

Parameter	Type	Description
`name`	string	Template name within the set
`data`	table	Variables to pass to template (optional)

Returns: string, error

Set Method Summary

The set handle provides these methods:

Method	Returns	Description
`render(name, data?)`	`string, error`	Render template with data
`release()`	`boolean`	Release set back to pool

Jet Syntax Reference

Jet uses {{ }} for expressions and control structures and {* *} for comments.

Variables

{{ user.name }}
{{ user.email }}
{{ items[0].price }}

Conditionals

{{ if order.shipped }}
    <p>Shipped!</p>
{{ else if order.processing }}
    <p>Processing...</p>
{{ else }}
    <p>Received.</p>
{{ end }}

Loops

{{ range items }}
    <li>{{ .name }} - ${{ .price }}</li>
{{ end }}

{{ range i, item := items }}
    <p>{{ i }}. {{ item.name }}</p>
{{ end }}

Inheritance

{* Parent: layout.jet *}
<html>
<head><title>{{ yield title() }}</title></head>
<body>{{ yield body() }}</body>
</html>

{* Child: page.jet *}
{{ extends "layout" }}
{{ block title() }}My Page{{ end }}
{{ block body() }}<p>Content</p>{{ end }}

Includes

{{ include "partials/header" }}
<main>Content</main>
{{ include "partials/footer" }}

Errors

Condition	Kind	Retryable
Empty ID	`errors.INVALID`	no
Empty template name	`errors.INVALID`	no
Permission denied	`errors.PERMISSION_DENIED`	no
Template set missing, unavailable, or wrong resource type	`errors.INTERNAL`	no
Template not found	`errors.NOT_FOUND`	no
Render error	`errors.INTERNAL`	no
Render attempted after the set was released	`errors.INTERNAL`	no

See Error Handling for working with errors.