# Lit-Only Architecture (No Build)
A minimal, no-build web application using only Lit web components with local state management.
> **Note:** This is the `lit-only` branch. For the full-featured version with Zustand state management and IndexedDB persistence, see the `main` branch.
## For TSX/React Developers
If you're coming from React/TSX, here's how this minimal architecture maps to familiar concepts:
| React/TSX Pattern | This Architecture |
|-------------------|-------------------|
| `useState` | Lit's `static properties` with `state: true` |
| Props drilling | Property passing via `.prop=${value}` |
| Custom events | `CustomEvent` with `bubbles: true` |
| JSX | Lit's `html` tagged template literals |
| CSS-in-JS / CSS Modules | Lit's `css` tagged template literals |
| React Router | Simple route state in root component |
| Build step (Vite/Webpack) | Import maps (no build!) |
### Key Differences
1. **No Virtual DOM**: Lit uses native Web Components with efficient DOM updates
2. **No Build Step**: Import maps let you use npm packages directly from CDN
3. **Local State Only**: Each component manages its own state, parent manages shared state
4. **Event-Based Communication**: Child components emit events, parent handles them
5. **Tagged Templates**: Instead of JSX, use `html\`
...
\``
## Architecture Overview
* **Lit-based web components** - Standards-based, framework-agnostic UI
* **No-build tooling** - Import maps only, no bundler required
* **Local state management** - Component properties and state
* **Event-driven** - CustomEvents for child-to-parent communication
## Project Structure
```
components/
app-root.js ← Root component with shared state
nav-bar.js ← Navigation component
page-home.js ← Home page component
page-items.js ← Items page component
index.html ← Entry point with inline importmap
README.md
tasks.md
```
## Data Flow Pattern
### Parent-to-Child (Props)
```javascript
// Parent passes data down
html``
// Child receives via properties
static properties = {
items: { type: Array }
}
```
### Child-to-Parent (Events)
```javascript
// Child emits event
this.dispatchEvent(new CustomEvent('add-item', {
detail: { item: newItem },
bubbles: true,
composed: true
}))
// Parent listens
html` this.handleAdd(e.detail.item)}>`
```
## State Management Pattern
```mermaid
graph TD
A[app-root] -->|.user, .items, .route| B[nav-bar]
A -->|.user, .items| C[page-home]
A -->|.items| D[page-items]
B -->|@navigate event| A
D -->|@add-item event| A
D -->|@remove-item event| A
style A fill:#f9f,stroke:#333,stroke-width:2px
style B fill:#bbf,stroke:#333,stroke-width:2px
style C fill:#bfb,stroke:#333,stroke-width:2px
style D fill:#bfb,stroke:#333,stroke-width:2px
```
## Quick Start Example
### 1. Define a Component
```javascript
// components/counter.js
import { LitElement, html, css } from 'lit'
class Counter extends LitElement {
static properties = {
count: { type: Number, state: true }
}
constructor() {
super()
this.count = 0
}
static styles = css`
button { padding: 1rem; font-size: 1.2rem; }
`
render() {
return html`
Count: ${this.count}
`
}
}
customElements.define('my-counter', Counter)
```
### 2. Use in HTML (no build step!)
```html
```
## Component Communication Patterns
### Pattern 1: Shared State in Root
```javascript
class AppRoot extends LitElement {
static properties = {
items: { type: Array, state: true }
}
constructor() {
super()
this.items = []
}
addItem(item) {
this.items = [...this.items, item]
}
render() {
return html`
this.addItem(e.detail.item)}
>
`
}
}
```
### Pattern 2: Local State in Component
```javascript
class MyComponent extends LitElement {
static properties = {
_draft: { type: String, state: true }
}
constructor() {
super()
this._draft = ''
}
render() {
return html`
this._draft = e.target.value}
/>
`
}
}
```
## Benefits Over React/TSX
✅ **No build step** - Edit and refresh, instant feedback
✅ **Minimal dependencies** - Just Lit, nothing else
✅ **Smaller bundle** - No framework runtime, just standards
✅ **Better encapsulation** - Shadow DOM, scoped styles
✅ **Framework agnostic** - Works anywhere, even in React apps
✅ **Future-proof** - Built on web standards
✅ **Easy to learn** - Simple mental model, no complex state management
## When to Use This vs. Full Stack
### Use Lit-Only When:
- Building small to medium apps
- Don't need persistence
- State is simple and hierarchical
- Want maximum simplicity
### Use Full Stack (main branch) When:
- Need IndexedDB persistence
- Complex state shared across many components
- Need cross-tab synchronization
- Want time-travel debugging
- Building larger applications
## See Also
- [tasks.md](./tasks.md) - Current issues and improvements
- [Lit Documentation](https://lit.dev)
- [Web Components](https://developer.mozilla.org/en-US/docs/Web/Web_Components)
- [Import Maps](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script/type/importmap)