sigpro/llms.txt

```txt
# SigPro Complete System Documentation

## Library Identity
SigPro is a zero-dependency reactive signal library (~5KB gzipped) for building reactive web applications with fine-grained reactivity, built-in DOM bindings, Web Components, routing, persistent storage, and WebSocket integration.

## Core Philosophy
- Signals are functions, not objects with .value
- Automatic dependency tracking (no manual declaration)
- Computed values cache until dependencies change
- DOM updates batched via microtask queue
- Everything reactive composes naturally

## Complete API Reference

### Core Signal: `$(initialValue)`
The fundamental reactive primitive.

**Overload 1: Regular Signal**
```javascript
const count = $(0);              // Initial value
count()                           // Get -> 0
count(5)                          // Set -> 5
count(prev => prev + 1)           // Update with function
count(prev => ({...prev, new: true})) // Object update
```

**Overload 2: Computed Signal**
```javascript
const doubled = $(() => count() * 2);  // Auto-detects count dependency
const fullName = $(() => `${firstName()} ${lastName()}`);
```

**Advanced Patterns:**
```javascript
// Lazy computed - only recalculates when accessed AND dependencies changed
const expensive = $(() => {
  console.log('Computing...');
  return data().filter(complexOperation);
});

// Computed with cleanup (rare but possible)
const withCleanup = $(() => {
  const temp = setup();
  return () => cleanup(temp); // Runs when dependencies change
});

// Circular dependency protection - throws error
const a = $(() => b());
const b = $(() => a()); // Error: Circular dependency detected
```

### Effect: `$.effect(fn)`
Automatic side effect runner with intelligent cleanup.

```javascript
// Basic tracking
$.effect(() => {
  console.log(`Count is: ${count()}`); // Re-runs when count changes
});

// Cleanup pattern
$.effect(() => {
  const timer = setInterval(() => {
    console.log('tick', count());
  }, 1000);
  
  // Return cleanup - runs BEFORE next effect run OR on stop
  return () => {
    clearInterval(timer);
    console.log('Cleaned up timer');
  };
});

// Nested effects - parent tracks child cleanup
$.effect(() => {
  const stopChild = $.effect(() => {
    // This child effect is automatically cleaned up
    // when parent re-runs or stops
  });
});

// Effect batching - multiple updates trigger one run
count(1);
count(2);
count(3); // Effect runs once with final value 3

// Manual stop
const stop = $.effect(() => {});
stop(); // Permanently stops effect, runs cleanup

// Effect within effect - parent tracks child
$.effect(() => {
  const data = fetchData();
  $.effect(() => {
    // This child effect will be auto-cleaned
    // when parent re-runs
    process(data());
  });
});

// Async effects - careful! Only sync dependencies tracked
$.effect(async () => {
  const id = userId(); // Tracked ✅
  const data = await fetch(`/api/${id}`); // Async
  // DO NOT access signals here - they won't be tracked!
  // Instead, move them before await or use separate effect
});
```

### DOM Template: `` html`...` ``
Complete reactive templating system.

**Text Interpolation:**
```javascript
// Basic
html`<div>Hello ${name}</div>`

// Reactive function
html`<div>Count: ${() => count()}</div>`

// Multiple values
html`<div>${() => a()} + ${() => b()} = ${() => a() + b()}</div>`

// Conditional rendering (falsy values: null/undefined/false render nothing)
html`<div>${() => isLoading() ? spinner : content}</div>`

// List rendering (array of nodes or strings)
html`<ul>${() => items.map(item => html`<li>${item}</li>`)}</ul>`

// Mixed content
html`<div>${() => [header, content, footer]}</div>`

// Fragment handling - auto-wraps multiple root nodes
html`
  <header>Title</header>
  <main>Content</main>
  <footer>Footer</footer>
` // Returns DocumentFragment with 3 children
```

**Event Directives - Complete Reference:**
```javascript
// Basic
html`<button @click=${handler}>Click</button>`

// Event object access
html`<input @input=${(e) => value(e.target.value)}>`

// All modifiers:
// prevent - e.preventDefault()
// stop - e.stopPropagation()
// once - auto-remove after first fire
// self - only if e.target === element
// debounce:ms - debounce handler
// passive - { passive: true }
// capture - use capture phase

// Examples
html`<a @click.prevent.stop=${handler} href="#">No navigation, no bubble</a>`
html`<input @input.debounce:500=${search} placeholder="Search">`
html`<button @click.once=${oneTime}>Only once</button>`
html`<div @scroll.passive=${onScroll}>Optimized scroll</div>`
html`<div @click.capture=${captureHandler}>Capture phase</div>`
html`<button @click.self=${selfHandler}>Only if button clicked, not children</button>`

// Multiple modifiers
html`<input @keydown.debounce:300.prevent.stop=${handler}>`

// Dynamic event handlers
html`<button @click=${() => show() ? handler1 : handler2}>`
```

**Two-way Binding: `:property`**
```javascript
// Text input
html`<input :value=${userName}>`

// Checkbox
html`<input type="checkbox" :checked=${isAdmin}>`

// Radio group
html`
  <input type="radio" name="size" value="small" :checked=${size === 'small'}>
  <input type="radio" name="size" value="large" :checked=${size === 'large'}>
`

// Select
html`
  <select :value=${selectedOption}>
    <option value="a">A</option>
    <option value="b">B</option>
  </select>
`

// Textarea
html`<textarea :value=${content}></textarea>`

// Custom elements
html`<my-input :value=${data}></my-input>`

// Updates happen on 'input' for text, 'change' for checkboxes/radios
// Two-way binding creates two effects automatically
```

**Boolean Attributes: `?attribute`**
```javascript
html`<button ?disabled=${isDisabled}>`
html`<input ?required=${isRequired}>`
html`<details ?open=${expanded}>`
html`<option ?selected=${isSelected}>`
html`<div ?hidden=${!visible}>`
// Attribute present if truthy, absent if falsy
```

**Property Binding: `.property`**
```javascript
html`<div .scrollTop=${scrollPosition}>`
html`<progress .value=${progress} .max=${100}>`
html`<video .currentTime=${timestamp} .volume=${volume}>`
html`<my-element .data=${complexObject}>` // Pass objects directly
html`<div .classList=${['active', 'visible']}>` // Set classList property

// Property binding sets both property AND attribute (unless object/boolean)
```

**Special Cases:**
```javascript
// SVG support
html`<svg width="100" height="100">
  <circle cx="50" cy="50" r=${() => radius()} fill="red"/>
</svg>`

// Self-closing tags
html`<img src=${imageUrl} alt=${altText}>`

// Comments - preserved in template
html`<!-- Header section --><h1>Title</h1>`

// Doctype - only at root
html`<!DOCTYPE html><html>...</html>`

// Template tag
html`<template>${() => repeatContent()}</template>`

// Slot handling
html`<my-component>${() => slottedContent}</my-component>`
```

### Component System: `$.component(tagName, setupFn, observedAttributes)`
Full Web Components integration with reactive properties.

**Complete Component Lifecycle:**
```javascript
$.component('my-counter', (props, ctx) => {
  // 1. Initialization phase
  console.log('Component initializing');
  
  // Local state (not exposed as attribute)
  const internalCount = $(0);
  
  // Computed from props
  const doubled = $(() => props.count() * 2);
  
  // 2. Setup side effects
  const stopEffect = $.effect(() => {
    console.log('Count changed:', props.count());
  });
  
  // 3. Register cleanup
  ctx.onUnmount(() => {
    console.log('Cleaning up');
    stopEffect();
  });
  
  // 4. Access DOM
  ctx.select('button')?.classList.add('primary');
  
  // 5. Handle slots
  const defaultSlot = ctx.slot(); // unnamed slots
  const headerSlot = ctx.slot('header'); // named slots
  
  // 6. Emit events
  const handleClick = () => {
    ctx.emit('increment', { value: props.count() });
    ctx.emit('counter-changed', { count: props.count() }, { bubbles: false }); // Custom options
  };
  
  // 7. Return template (must return Node or DocumentFragment)
  return html`
    <div class="counter">
      <slot name="header">Default header</slot>
      <button @click=${handleClick}>
        Count: ${() => props.count()}
      </button>
      <slot>Default content</slot>
    </div>
  `;
}, ['count', 'min', 'max']); // Observed attributes

// Usage examples:
const el = document.createElement('my-counter');
el.count = 5;                    // Set property
el.setAttribute('min', '0');      // Set attribute
el.min = 10;                      // Property takes precedence
console.log(el.count);            // Get property -> 10
console.log(el.getAttribute('count')); // Get attribute -> "10"

// Special attribute conversion:
el.disabled = '';                 // true (except for 'value')
el.disabled = 'false';            // false
el.value = '';                    // "" (empty string preserved)
el.checked = 'false';             // false

// Event listening:
el.addEventListener('increment', (e) => {
  console.log(e.detail); // { value: x }
});

// Dynamic component creation:
const container = document.getElementById('app');
container.innerHTML = '<my-counter count="5"></my-counter>';

// Or programmatically:
const counter = new (customElements.get('my-counter'))();
counter.count = 5;
container.appendChild(counter);
```

**Advanced Component Patterns:**
```javascript
// Context/provider pattern
$.component('theme-provider', (props, ctx) => {
  const theme = $(props.theme());
  
  // Provide to children via custom event
  ctx.emit('theme-provider', { theme });
  
  return html`<slot></slot>`;
}, ['theme']);

$.component('themed-button', (props, ctx) => {
  const theme = $('light');
  
  // Consume from parent
  ctx.host.addEventListener('theme-provider', (e) => {
    theme(e.detail.theme);
  });
  
  return html`<button class=${() => theme()}>Click</button>`;
});

// Compound components
$.component('tabs', (props, ctx) => {
  const activeTab = $(0);
  
  return html`
    <div class="tabs">
      <div class="tab-headers">
        ${() => props.tabs().map((tab, i) => html`
          <button @click=${() => activeTab(i)}>${tab.title}</button>
        `)}
      </div>
      <div class="tab-content">
        ${() => props.tabs()[activeTab()].content}
      </div>
    </div>
  `;
}, ['tabs']);

// Form association
$.component('my-input', (props, ctx) => {
  // Integrate with parent forms
  const form = ctx.host.closest('form');
  if (form) {
    form.addEventListener('reset', () => {
      props.value(props.defaultValue());
    });
  }
  
  return html`<input :value=${props.value}>`;
}, ['value', 'defaultValue']);
```

### Persistent Storage: `$.storage(key, initialValue, storage?)`
Automatic persistence with change detection.

```javascript
// Basic localStorage
const settings = $.storage('app-settings', { theme: 'light' });
settings({ ...settings(), theme: 'dark' }); // Auto-saves

// Session storage
const tempData = $.storage('temp', null, sessionStorage);

// Multiple stores
const userPrefs = $.storage('user-prefs', {});
const appState = $.storage('app-state', {});

// Auto-cleanup
const cache = $.storage('cache', {});
cache(null); // Removes from storage

// Complex objects - automatic JSON serialization
const complex = $.storage('complex', {
  date: new Date(),
  regex: /pattern/,
  nested: { array: [1,2,3] }
});

// Storage events - auto sync across tabs
window.addEventListener('storage', (e) => {
  if (e.key === 'app-settings') {
    // Signal auto-updates on next read
  }
});

// Migration pattern
const data = $.storage('v2-data', () => {
  // Migration from v1
  const old = localStorage.getItem('v1-data');
  return old ? migrate(JSON.parse(old)) : defaultValue;
});

// Computed from storage
const config = $(() => {
  const base = settings();
  return { ...base, computed: derive(base) };
});
```

### Router: `$.router(routes)` and `$.router.go()`
Hash-based routing with parameter extraction.

```javascript
// Route definitions - comprehensive examples
const router = $.router([
  // Static routes
  { path: '/', component: () => html`<home-page></home-page>` },
  { path: '/about', component: () => html`<about-page></about-page>` },
  
  // Parameterized routes
  { 
    path: '/users/:id', 
    component: (params) => html`<user-profile user-id=${params.id}></user-profile>`
  },
  { 
    path: '/posts/:postId/comments/:commentId',
    component: (params) => html`
      <div>
        Post ${params.postId}, Comment ${params.commentId}
      </div>
    `
  },
  
  // Regex routes with capture groups
  { 
    path: /^\/products\/(?<category>\w+)\/(?<id>\d+)$/,
    component: (params) => html`
      <product-view 
        category=${params.category} 
        id=${params.id}
      ></product-view>
    `
  },
  {
    path: /\/archive\/(\d{4})\/(\d{2})/,
    component: (params) => html`Archive: ${params[0]}-${params[1]}`
  },
  
  // Query parameter handling (manual)
  {
    path: '/search',
    component: () => {
      const searchParams = new URLSearchParams(window.location.search);
      return html`<search-results query=${searchParams.get('q')}></search-results>`;
    }
  },
  
  // Nested routers
  {
    path: '/dashboard',
    component: () => {
      return $.router([
        { path: '/', component: dashboardHome },
        { path: '/settings', component: dashboardSettings }
      ]);
    }
  },
  
  // Guard pattern
  {
    path: '/admin',
    component: (params) => {
      if (!isAuthenticated()) {
        $.router.go('/login');
        return html`<!-- Empty, redirecting -->`;
      }
      return html`<admin-panel></admin-panel>`;
    }
  },
  
  // Catch-all / 404
  {
    path: /.*/,
    component: () => html`<not-found></not-found>`
  }
]);

// Navigation
$.router.go('/users/123');           // Basic
$.router.go('users/123');             // Auto-adds leading slash
$.router.go('/search?q=test');        // Query strings preserved

// Advanced navigation
const navigateWithState = (path, state) => {
  history.replaceState(state, '', `#${path}`);
  window.dispatchEvent(new HashChangeEvent('hashchange'));
};

// Route change detection
window.addEventListener('hashchange', () => {
  console.log('Route changed to:', window.location.hash);
});

// Current route signal (if needed)
const currentRoute = $(() => window.location.hash.replace(/^#/, '') || '/');

// Route params as signals
const routeParams = $(null);
$.effect(() => {
  const match = currentRoute().match(/\/users\/(\d+)/);
  routeParams(match ? { id: match[1] } : null);
});

// Lazy loading routes
const router = $.router([
  { 
    path: '/heavy', 
    component: async (params) => {
      const module = await import('./heavy-page.js');
      return module.default(params);
    }
  }
]);
```

### Fetch: `$.fetch(url, data, loading?)`
Simplified data fetching with loading state.

```javascript
// Basic usage
const result = await $.fetch('/api/users', { id: 123 });

// With loading signal
const isLoading = $(false);
const data = await $.fetch('/api/search', { query: 'test' }, isLoading);
console.log(isLoading()); // false after completion

// Error handling (returns null on error)
const result = await $.fetch('/api/fail', {}) || fallbackData;

// Integration with signals
const userData = $(null);
const loading = $(false);

async function loadUser(id) {
  userData(await $.fetch(`/api/users/${id}`, {}, loading));
}

// Reactive fetch with effect
$.effect(() => {
  const id = currentUserId();
  loadUser(id);
});

// Retry logic wrapper
async function fetchWithRetry(url, data, retries = 3) {
  for (let i = 0; i < retries; i++) {
    const result = await $.fetch(url, data);
    if (result) return result;
    await new Promise(r => setTimeout(r, 1000 * Math.pow(2, i)));
  }
  return null;
}

// Request cancellation
let abortController = null;

$.effect(() => {
  if (abortController) abortController.abort();
  abortController = new AbortController();
  
  const id = userId();
  fetch(`/api/user/${id}`, { signal: abortController.signal })
    .then(r => r.json())
    .then(data => userData(data));
});
```

### WebSocket: `$.ws(url, options)`
Full-featured WebSocket client with reactive state.

```javascript
// Basic connection
const ws = $.ws('wss://api.example.com/ws');

// With options
const ws = $.ws('wss://api.example.com/ws', {
  reconnect: true,
  maxReconnect: 10,
  reconnectInterval: 2000 // Base interval for exponential backoff
});

// Reactive state
$.effect(() => {
  console.log('Status:', ws.status());      // 'connecting', 'connected', 'disconnected', 'error'
  console.log('Messages:', ws.messages());  // Array of received messages
  console.log('Error:', ws.error());        // Last error or null
});

// Sending messages
ws.send({ type: 'join', room: 'general' });
ws.send('plain text message');

// Auto-reconnect with backoff
// Attempts: 2s, 4s, 8s, 16s, 32s (until maxReconnect)

// Message filtering
const commands = $(() => ws.messages().filter(m => m.type === 'command'));
const events = $(() => ws.messages().filter(m => m.type === 'event'));

// Send with acknowledgment
async function sendWithAck(data, timeout = 5000) {
  return new Promise((resolve, reject) => {
    const id = Math.random();
    const message = { ...data, id };
    
    const handler = (msg) => {
      if (msg.ack === id) {
        ws.messages.off(handler);
        resolve(msg);
      }
    };
    
    // Need message event listener pattern
    const timeoutId = setTimeout(() => {
      ws.messages.off(handler);
      reject(new Error('Ack timeout'));
    }, timeout);
    
    // Custom listener would be needed for this pattern
    ws.send(message);
  });
}

// Reconnection handling
$.effect(() => {
  if (ws.status() === 'connected') {
    console.log('Connected, sending init...');
    ws.send({ type: 'init', token: authToken() });
  }
});

// Binary data
const ws = $.ws('wss://example.com/binary');
ws.send(new Blob([data]));
ws.send(new ArrayBuffer(8));

// Heartbeat / ping-pong
$.effect(() => {
  if (ws.status() !== 'connected') return;
  
  const interval = setInterval(() => {
    ws.send({ type: 'ping' });
  }, 30000);
  
  return () => clearInterval(interval);
});

// Queue messages while disconnected
const messageQueue = $([]);
$.effect(() => {
  if (ws.status() === 'connected') {
    messageQueue().forEach(msg => ws.send(msg));
    messageQueue([]);
  }
});

function sendOrQueue(data) {
  if (ws.status() === 'connected') {
    ws.send(data);
  } else {
    messageQueue([...messageQueue(), data]);
  }
}
```

### Advanced Patterns & Best Practices

**State Management Patterns:**
```javascript
// Store pattern
const createStore = (initial) => {
  const state = $(initial);
  
  return {
    state,
    actions: {
      update: (fn) => state(fn(state())),
      reset: () => state(initial)
    }
  };
};

// Selector pattern
const selectUser = (id) => $(() => 
  users().find(u => u.id === id)
);

// Computed selector
const selectVisibleTodos = $(() => 
  todos().filter(t => 
    filter() === 'all' || 
    (filter() === 'active' && !t.completed) ||
    (filter() === 'completed' && t.completed)
  )
);

// Action pattern
const increment = () => count(c => c + 1);
const addTodo = (text) => todos(t => [...t, { text, completed: false }]);
const toggleTodo = (id) => todos(t => t.map(todo => 
  todo.id === id ? { ...todo, completed: !todo.completed } : todo
));
```

**Performance Optimization:**
```javascript
// Memoization
const expensiveComputation = $(() => {
  console.log('Computing...');
  return bigData().filter(heavyFilter).map(transform);
});

// Batch updates
count(1);
count(2);
count(3); // Single effect run

// Manual flush if needed
import { flushEffectQueue } from 'sigpro';
flushEffectQueue(); // Force immediate effect processing

// Lazy computed - only computes when accessed
const lazyValue = $(() => {
  if (!cache) cache = expensive();
  return cache;
});

// Effect debouncing
let timeout;
$.effect(() => {
  clearTimeout(timeout);
  timeout = setTimeout(() => {
    console.log('Debounced:', value());
  }, 100);
});
```

**Error Boundaries & Recovery:**
```javascript
// Effect error handling
$.effect(() => {
  try {
    riskyOperation();
  } catch (e) {
    errorSignal(e);
  }
});

// Component error boundary
$.component('error-boundary', (props, ctx) => {
  const error = $(null);
  
  const handleError = (e) => {
    error(e.error);
    e.preventDefault();
  };
  
  ctx.host.addEventListener('error', handleError);
  ctx.onUnmount(() => ctx.host.removeEventListener('error', handleError));
  
  return () => error() 
    ? html`<error-display error=${error()}></error-display>`
    : html`<slot></slot>`;
});

// Global error handler
window.addEventListener('error', (e) => {
  console.error('SigPro error:', e.error);
});
```

**Testing Utilities:**
```javascript
// Test helper pattern
const createTestHarness = () => {
  const effects = [];
  const origEffect = $.effect;
  
  $.effect = (fn) => {
    const stop = origEffect(fn);
    effects.push(stop);
    return stop;
  };
  
  return {
    cleanup: () => effects.forEach(stop => stop()),
    restore: () => { $.effect = origEffect; }
  };
};

// Async test helper
const waitForEffect = () => new Promise(r => setTimeout(r, 0));

// Usage in tests
test('counter increments', async () => {
  const count = $(0);
  const calls = [];
  
  $.effect(() => {
    calls.push(count());
  });
  
  count(1);
  await waitForEffect(); // Wait for effect queue
  expect(calls).toEqual([0, 1]);
});
```

**TypeScript Integration (conceptual):**
```typescript
// Type patterns (even though library is JS)
type Signal<T> = {
  (): T;
  (value: T | ((prev: T) => T)): void;
};

type Computed<T> = () => T;

type Effect = (fn: () => (void | (() => void))) => () => void;

// Component props typing
interface ComponentProps {
  [key: string]: Signal<any>;
}

interface ComponentContext {
  select: (selector: string) => Element | null;
  slot: (name?: string) => Node[];
  emit: (name: string, detail?: any, options?: CustomEventInit) => void;
  host: HTMLElement;
  onUnmount: (fn: () => void) => void;
}
```

**Migration from Other Frameworks:**
```javascript
// From Vue:
// ref(0) -> $(0)
// computed -> $(() => value)
// watch -> $.effect
// onMounted -> $.effect (runs immediately)

// From React:
// useState -> $ (but get/set combined)
// useEffect -> $.effect
// useMemo -> $(() => value)
// useCallback -> Just use function, dependencies automatic

// From Svelte:
// let count = 0 -> const count = $(0)
// $: doubled = count * 2 -> const doubled = $(() => count())
```

## Internal Architecture (for deep understanding)

```javascript
// Reactivity graph structure
{
  activeEffect: Effect | null,           // Currently executing effect
  effectQueue: Set<Effect>,               // Pending effects
  signal: {
    subscribers: Set<Effect>,              // Effects depending on this signal
    value: any,                            // Current value
    isDirty?: boolean                       // For computed signals
  },
  effect: {
    dependencies: Set<Set<Effect>>,        // Signals this effect depends on
    cleanupHandlers: Set<Function>,         // Cleanup functions
    markDirty?: Function                     // For computed signal effects
  }
}

// Flush mechanism
// 1. Signal update adds affected effects to queue
// 2. Schedules microtask flush
// 3. Effects run in order added
// 4. Each effect cleans up old dependencies
// 5. New dependencies tracked during run
```

## Complete Example Application

```javascript
// app.js
import { $, html, $.component, $.router, $.storage, $.ws } from 'sigpro';

// State
const todos = $.storage('todos', []);
const filter = $('all');
const user = $(null);
const ws = $.ws('wss://api.example.com/todos');

// Computed
const filteredTodos = $(() => {
  const all = todos();
  switch(filter()) {
    case 'active': return all.filter(t => !t.completed);
    case 'completed': return all.filter(t => t.completed);
    default: return all;
  }
});

const stats = $(() => {
  const all = todos();
  return {
    total: all.length,
    active: all.filter(t => !t.completed).length,
    completed: all.filter(t => t.completed).length
  };
});

// Actions
const addTodo = (text) => {
  const newTodo = {
    id: Date.now(),
    text,
    completed: false,
    createdAt: new Date().toISOString()
  };
  todos([...todos(), newTodo]);
  ws.send({ type: 'add', todo: newTodo });
};

const toggleTodo = (id) => {
  todos(todos().map(t => 
    t.id === id ? { ...t, completed: !t.completed } : t
  ));
};

const removeTodo = (id) => {
  todos(todos().filter(t => t.id !== id));
};

// Sync with WebSocket
$.effect(() => {
  ws.messages().forEach(msg => {
    if (msg.type === 'sync') {
      todos(msg.todos);
    }
  });
});

// Components
$.component('todo-app', () => html`
  <div class="app">
    <header>
      <h1>Todo App</h1>
      <todo-stats stats=${() => stats()}></todo-stats>
    </header>
    
    <todo-input @add=${(e) => addTodo(e.detail)}></todo-input>
    
    <div class="filters">
      <button @click=${() => filter('all')} ?active=${() => filter() === 'all'}>
        All (${() => stats().total})
      </button>
      <button @click=${() => filter('active')} ?active=${() => filter() === 'active'}>
        Active (${() => stats().active})
      </button>
      <button @click=${() => filter('completed')} ?active=${() => filter() === 'completed'}>
        Completed (${() => stats().completed})
      </button>
    </div>
    
    <todo-list 
      todos=${() => filteredTodos()}
      @toggle=${(e) => toggleTodo(e.detail)}
      @remove=${(e) => removeTodo(e.detail)}
    ></todo-list>
    
    ${() => ws.status() !== 'connected' ? html`
      <div class="offline-banner">
        Offline - ${() => ws.status()}
      </div>
    ` : ''}
  </div>
`);

$.component('todo-input', (props, ctx) => {
  const text = $('');
  
  const handleSubmit = () => {
    if (text().trim()) {
      ctx.emit('add', text().trim());
      text('');
    }
  };
  
  return html`
    <div class="todo-input">
      <input 
        :value=${text}
        @keydown.enter=${handleSubmit}
        placeholder="What needs to be done?"
      >
      <button @click=${handleSubmit}>Add</button>
    </div>
  `;
});

$.component('todo-list', (props) => html`
  <ul class="todo-list">
    ${() => props.todos().map(todo => html`
      <li class=${() => todo.completed ? 'completed' : ''}>
        <input 
          type="checkbox" 
          :checked=${() => todo.completed}
          @change=${() => props.emit('toggle', todo.id)}
        >
        <span>${todo.text}</span>
        <button @click=${() => props.emit('remove', todo.id)}>×</button>
      </li>
    `)}
  </ul>
`, ['todos']);

$.component('todo-stats', (props) => html`
  <div class="stats">
    <span>Total: ${() => props.stats().total}</span>
    <span>Active: ${() => props.stats().active}</span>
    <span>Completed: ${() => props.stats().completed}</span>
  </div>
`, ['stats']);

// Router setup
const router = $.router([
  { path: '/', component: () => html`<todo-app></todo-app>` },
  { path: '/settings', component: () => html`<settings-page></settings-page>` },
  { path: '/about', component: () => html`<about-page></about-page>` }
]);

// Mount app
document.body.appendChild(router);
```