trellis 0.6.0 
trellis: ^0.6.0 copied to clipboard
leafnode.seTemplate engine for Dart, using natural HTML templates. Fragment-first for hypermedia-driven frameworks like HTMX. Inspired by Thymeleaf.
Trellis Examples #
Quick Start #
import 'package:trellis/trellis.dart';
void main() {
final engine = Trellis(loader: MapLoader({}));
final html = engine.render(
'<h1 tl:text="\${title}">Default</h1>',
{'title': 'Hello, Trellis!'},
);
print(html); // <html><head></head><body><h1>Hello, Trellis!</h1></body></html>
// Fragment rendering for HTMX partial responses
const template = '''
<ul tl:fragment="items">
<li tl:each="item : \${items}" tl:text="\${item}">placeholder</li>
</ul>
''';
final fragment = engine.renderFragment(
template,
fragment: 'items',
context: {'items': ['Alpha', 'Beta', 'Gamma']},
);
print(fragment); // <ul><li>Alpha</li><li>Beta</li><li>Gamma</li></ul>
}
Examples #
basic/ -- API Demos #
Self-contained examples showing core trellis features with inline templates.
cd example/basic
dart pub get
dart run bin/example.dart # Template features: text, if, each, switch, fragments
dart run bin/shelf_example.dart # Shelf integration pattern
todo_app/ -- Full Shelf + HTMX App #
A complete server-side rendered todo application demonstrating trellis with Shelf and HTMX.
Features demonstrated:
- External
.htmltemplate files (natural templates) - Fragment-first architecture for HTMX partial responses
tl:each,tl:if,tl:unless,tl:text,tl:attr,tl:classappend,tl:with,tl:insertrenderFile()for full pages,renderFragment()/renderFragments()for HTMX partials- Custom filters (
date,capitalize) - In-memory data store with CRUD operations
cd example/todo_app
dart pub get
dart run bin/server.dart
# Open http://localhost:8080
Project structure
todo_app/
├── bin/server.dart # Shelf server, Trellis engine setup, route registration
├── lib/
│ ├── handlers.dart # Route handlers — rendering logic and fragment strategy
│ ├── models.dart # TodoList and Todo data models with toMap() for templates
│ └── store.dart # In-memory CRUD store
├── templates/
│ └── app.html # Single template file — full page + all named fragments
└── static/
└── styles.css # Application styles
Key architectural concepts
Single template file — app.html serves as both the full-page template and the
source of all named fragments (sidebar, main-content, todo-list, todo-row).
renderFile() renders the whole document; renderFragments() extracts specific
sections for HTMX partial responses. See the comment block at the top of app.html
for details, including how to split fragments across multiple files instead.
Two render strategies — handlers choose between two fragment combinations depending
on what changed. Todo CRUD operations return todo-list + OOB sidebar (counts
update, header stays). List navigation/mutation returns main-content + OOB sidebar
(full main area replaced including header). See handlers.dart for the rationale.
OOB sidebar — the sidebar carries hx-swap-oob="true", so a single HTMX response
can update both the primary target and the sidebar counts simultaneously.
todoCount as integer — Trellis treats empty lists as truthy (unlike Thymeleaf),
so tl:if="${todos}" would never hide the empty state. tl:if="${todoCount}" (where
0 is falsy) is the correct pattern for empty-collection guards in Trellis.
Metadata
Documentation
Publisher
Weekly Downloads
Metadata
Template engine for Dart, using natural HTML templates. Fragment-first for hypermedia-driven frameworks like HTMX. Inspired by Thymeleaf.
Repository (GitHub)
View/report issues
Topics
#template #html #htmx #server-side-rendering
License
MIT (license)
Dependencies
args, html, matcher, string_scanner
