Template Engine

Render dynamic content using the Jet template engine. Build HTML pages, emails, and documents with template inheritance and includes.

For template set configuration, see Template Engine.

Loading

local templates = require("templates")

Acquiring Template Sets

Get a template set by registry ID to start rendering:

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

-- Use the set...

set:release()

Parameter	Type	Description
`id`	string	Template set registry ID

Returns: Set, error

Rendering Templates

Render a template by name with data:

local set = templates.get("app.views:emails")

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

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

set:release()
return html

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

Returns: string, error

Set 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, {* *} 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 not found	`errors.NOT_FOUND`	no
Render error	`errors.INTERNAL`	no
Set already released	`errors.INTERNAL`	no

See Error Handling for working with errors.