### Quick Start: Dexie Sync Kit Setup

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Demonstrates the basic setup for Dexie Sync Kit, including database definition, route configuration, and starting the sync engine.

```typescript
import Dexie from 'dexie';
import { startSync, defineRoutes } from '@dexie-kit/sync';

// 1. Define your database
const db = new Dexie('myapp');
db.version(1).stores({
  posts: '++id, title, updatedAt',
  comments: '++id, postId, content, updatedAt',
});

// 2. Configure sync routes
const routes = defineRoutes({
  posts: {
    push: {
      create: {
        method: 'POST',
        url: '/api/posts',
        body: (item) => item,
      },
      update: {
        method: 'PUT',
        url: (item) => `/api/posts/${item.id}`,
        body: (item) => item,
      },
      delete: {
        method: 'DELETE',
        url: (item) => `/api/posts/${item.id}`,
      },
    },
    pull: {
      method: 'GET',
      url: '/api/posts',
      query: async (ctx) => ({
        updated_after: await ctx.getCheckpoint('pull:posts') || 0,
      }),
      mapResponse: (response) => response.data,
      onComplete: async (response, ctx) => {
        const latest = Math.max(
          ...response.data.map(p => new Date(p.updatedAt).getTime())
        );
        await ctx.setCheckpoint('pull:posts', latest);
      },
    },
  },
});

// 3. Start sync
const syncEngine = startSync(db, {
  baseUrl: 'https://api.example.com',
  
  auth: {
    getHeaders: async () => ({
      'Authorization': `Bearer ${await getToken()}`,
    }),
  },
  
  routes,
  
  conflicts: {
    policy: 'server-wins',
  },
  
  sync: {
    interval: 30000, // Sync every 30 seconds
    onOnline: true,  // Sync when coming online
  },
});

// 4. Use your app normally
await db.posts.add({ title: 'Hello World' });

// Sync happens automatically!
await syncEngine.start();

```

--------------------------------

### Dexie Sync Kit Setup and Usage

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/.github-summary.md

Demonstrates how to initialize and start the Dexie Sync Kit for offline-first synchronization with a REST API. Includes defining database schema, configuring sync routes, and handling data synchronization.

```typescript
import Dexie from 'dexie';
import { startSync, defineRoutes } from '@dexie-kit/sync';

const db = new Dexie('myapp');
db.version(1).stores({
  posts: '++id, title, updatedAt',
});

const syncEngine = startSync(db, {
  baseUrl: 'https://api.example.com',
  auth: { getHeaders: async () => ({ Authorization: `Bearer ${token}` }) },
  routes: defineRoutes({
    posts: {
      push: {
        create: { method: 'POST', url: '/api/posts' },
        update: { method: 'PUT', url: (item) => `/api/posts/${item.id}` },
        delete: { method: 'DELETE', url: (item) => `/api/posts/${item.id}` },
      },
      pull: {
        method: 'GET',
        url: '/api/posts',
        query: async (ctx) => ({ updated_after: await ctx.getCheckpoint('pull:posts') || 0 }),
        mapResponse: (res) => res.data,
        onComplete: async (res, ctx) => {
          const latest = Math.max(...res.data.map(p => new Date(p.updatedAt).getTime()));
          await ctx.setCheckpoint('pull:posts', latest);
        },
      },
    },
  }),
  conflicts: { policy: 'server-wins' },
  sync: { interval: 30000, onOnline: true },
});

await syncEngine.start();

// Use Dexie normally - sync happens automatically!
await db.posts.add({ title: 'Hello World', updatedAt: new Date() });

```

--------------------------------

### Install Dependencies

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Install all necessary project dependencies using npm.

```bash
npm install
```

--------------------------------

### Install Dexie Sync Kit and Dexie

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Install the necessary packages for Dexie Sync Kit and Dexie.js using npm.

```bash
npm install @dexie-kit/sync dexie
```

--------------------------------

### Example Commit Message

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Follow this format for clear and concise commit messages, starting with a verb and keeping the subject line brief.

```git
Add support for custom pagination strategies

- Implement cursor-based pagination
- Add offset-based pagination
- Update documentation with examples
```

--------------------------------

### startSync Function

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Initializes and starts the synchronization engine for a given Dexie database instance with a specified configuration.

```APIDOC
## startSync(db, config)

### Description
Starts sync for a Dexie database.

### Parameters
- `db` (Dexie) - Your Dexie database instance
- `config` (SyncConfig) - Sync configuration

### Returns
`SyncEngine`
```

--------------------------------

### Example Workflow - Commit and Push Changes

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/PUBLISHING.md

After making changes and creating a changeset, commit them and push to your feature branch.

```bash
git add .
git commit -m "feat: add custom retry strategies"
git push origin feature/my-feature
```

--------------------------------

### Backend API Endpoints for Dexie Sync

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/examples/basic-usage.md

These JavaScript examples illustrate the required backend API endpoints for handling GET, POST, PUT, and DELETE requests for posts, as expected by the Dexie Sync Kit configuration. They include logic for querying based on update time, creating, updating with version checks, and deleting resources.

```javascript
// GET /api/posts?updated_after=1234567890&limit=100
app.get('/api/posts', async (req, res) => {
  const { updated_after = '0', limit = '100' } = req.query;
  
  const posts = await db.posts.findMany({
    where: {
      updatedAt: { gt: new Date(Number(updated_after)) }
    },
    orderBy: { updatedAt: 'asc' },
    take: Number(limit)
  });
  
  res.json({ data: posts });
});

// POST /api/posts
app.post('/api/posts', async (req, res) => {
  const post = await db.posts.create({
    data: {
      ...req.body,
      updatedAt: new Date(),
      version: 1
    }
  });
  res.status(201).json(post);
});

// PUT /api/posts/:id
app.put('/api/posts/:id', async (req, res) => {
  const { expectedVersion, ...data } = req.body;
  
  const current = await db.posts.findUnique({
    where: { id: req.params.id }
  });
  
  if (!current) {
    return res.status(404).json({ error: 'Not found' });
  }
  
  // Check version for conflict detection
  if (expectedVersion && current.version !== expectedVersion) {
    return res.status(409).json({
      error: 'Version conflict',
      serverVersion: current.version,
      serverData: current
    });
  }
  
  const updated = await db.posts.update({
    where: { id: req.params.id },
    data: {
      ...data,
      version: current.version + 1,
      updatedAt: new Date()
    }
  });
  
  res.json(updated);
});

// DELETE /api/posts/:id
app.delete('/api/posts/:id', async (req, res) => {
  await db.posts.delete({ where: { id: req.params.id } });
  res.status(204).send();
});

```

--------------------------------

### Dexie Sync Kit Setup and Configuration

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/examples/basic-usage.md

This snippet shows how to define your Dexie database, configure API routes for push and pull operations, set up authentication, handle conflicts, and initialize the sync engine. It's used for setting up the core synchronization logic.

```typescript
import Dexie from 'dexie';
import { startSync, defineRoutes } from '@dexie-kit/sync';

// 1. Define your database
const db = new Dexie('myapp');
db.version(1).stores({
  posts: '++id, title, content, updatedAt, version',
  comments: '++id, postId, content, updatedAt',
});

// 2. Configure routes
const routes = defineRoutes({
  posts: {
    // Push configuration (local -> server)
    push: {
      create: {
        method: 'POST',
        url: '/api/posts',
        body: (item) => ({
          title: item.title,
          content: item.content,
          updatedAt: item.updatedAt,
        }),
      },
      update: {
        method: 'PUT',
        url: (item) => `/api/posts/${item.id}`,
        body: (item) => ({
          title: item.title,
          content: item.content,
          updatedAt: item.updatedAt,
          version: item.version,
        }),
      },
      delete: {
        method: 'DELETE',
        url: (item) => `/api/posts/${item.id}`,
      },
    },

    // Pull configuration (server -> local)
    pull: {
      method: 'GET',
      url: '/api/posts',
      query: async (ctx) => {
        const lastSync = await ctx.getCheckpoint('pull:posts');
        return {
          updated_after: lastSync || 0,
          limit: 100,
        };
      },
      mapResponse: (response) => response.data,
      onComplete: async (response, ctx) => {
        if (response.data.length > 0) {
          const latest = Math.max(
            ...response.data.map((p: any) => new Date(p.updatedAt).getTime())
          );
          await ctx.setCheckpoint('pull:posts', latest);
        }
      },
    },
  },
});

// 3. Start sync
const syncEngine = startSync(db, {
  baseUrl: 'https://api.example.com',
  
  auth: {
    getHeaders: async () => {
      // Get your auth token
      const token = localStorage.getItem('auth_token');
      return {
        'Authorization': `Bearer ${token}`,
      };
    },
    onAuthError: async (error) => {
      if (error.status === 401) {
        // Refresh token or redirect to login
        console.log('Auth error, please login again');
      }
    },
  },
  
  routes,
  
  conflicts: {
    policy: 'server-wins', // or 'client-wins', 'lww', 'custom'
  },
  
  sync: {
    interval: 30000, // Sync every 30 seconds
    onOnline: true,  // Sync when coming online
  },
});

// 4. Start the sync engine
await syncEngine.start();

// 5. Use your app normally
await db.posts.add({
  title: 'My First Post',
  content: 'Hello World!',
  updatedAt: new Date().toISOString(),
  version: 1,
});

// Changes are automatically queued and synced!

// Listen to events
syncEngine.on('sync-complete', (result) => {
  console.log('Sync complete:', result);
  console.log(`Pushed: ${result.push.pushed}, Pulled: ${result.pull.pulled}`);
});

syncEngine.on('sync-error', (error) => {
  console.error('Sync failed:', error);
});

// Manually trigger sync
await syncEngine.sync();

// Check status
const status = syncEngine.getStatus();
console.log('Status:', status);

// Get metrics
const metrics = await syncEngine.getMetrics();
console.log('Queue depth:', metrics.queue.depth);
console.log('Last sync:', new Date(metrics.sync.lastSyncCompleted));

```

--------------------------------

### Express.js Backend Example for Posts API

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

This example demonstrates how to implement CRUD endpoints for a 'posts' resource using Express.js and Dexie.js, including timestamp filtering for delta queries.

```typescript
app.get('/api/posts', async (req, res) => {
  const { updated_after = '0' } = req.query;
  
  const posts = await db.posts.findMany({
    where: {
      updatedAt: { gt: new Date(Number(updated_after)) }
    },
    orderBy: { updatedAt: 'asc' }
  });
  
  res.json({ data: posts });
});

app.post('/api/posts', async (req, res) => {
  const post = await db.posts.create({
    data: { ...req.body, updatedAt: new Date() }
  });
  res.status(201).json(post);
});

app.put('/api/posts/:id', async (req, res) => {
  const post = await db.posts.update({
    where: { id: req.params.id },
    data: { ...req.body, updatedAt: new Date() }
  });
  res.json(post);
});

app.delete('/api/posts/:id', async (req, res) => {
  await db.posts.delete({ where: { id: req.params.id } });
  res.status(204).send();
});
```

--------------------------------

### Create a New Feature Branch

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Start a new branch for your feature development, following a consistent naming convention.

```bash
git checkout -b feature/your-feature-name
```

--------------------------------

### SyncEngine Lifecycle Methods

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Control the lifecycle of the sync engine. Use these methods to start, stop, pause, or resume synchronization.

```typescript
// Lifecycle
await syncEngine.start();
await syncEngine.stop();
await syncEngine.pause();
await syncEngine.resume();
```

--------------------------------

### Create a Changeset

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/PUBLISHING.md

Run this command to initiate the creation of a changeset file, which prompts for version type and change summary.

```bash
npm run changeset
```

--------------------------------

### Build the Project

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Compile the project's code into distributable artifacts.

```bash
npm run build
```

--------------------------------

### Manual Publishing - Build and Publish

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/PUBLISHING.md

Execute this command to manually build the package and publish it to npm. This is a fallback for automated workflows.

```bash
npm run release
```

--------------------------------

### Clone the Repository

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Clone your forked repository to your local machine and navigate into the project directory.

```bash
git clone https://github.com/YOUR_USERNAME/dexie-kit-sync.git
cd dexie-kit-sync
```

--------------------------------

### Run Tests

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Execute the project's test suite to ensure code quality and functionality.

```bash
npm test
```

--------------------------------

### Full Dexie Sync Kit Configuration

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

This snippet shows a comprehensive configuration for Dexie Sync Kit, covering sync intervals, authentication, push/pull strategies, conflict resolution, error handling, and observability.

```typescript
startSync(db, {
  baseUrl: 'https://api.example.com',
  
  routes: {
    // ... route config
  },
  
  auth: {
    getHeaders: async () => ({
      'Authorization': `Bearer ${token}`,
    }),
    onAuthError: async (error) => {
      if (error.status === 401) {
        await refreshToken();
      }
    },
    maxAuthRetries: 3,
  },
  
  sync: {
    interval: 30000,
    onOnline: true,
    onVisibilityChange: true,
    
    push: {
      batchSize: 10,
      concurrency: 3,
    },
    
    pull: {
      pageSize: 100,
      maxPages: 10,
    },
  },
  
  conflicts: {
    policy: 'lww',
    onConflict: async (conflict) => {
      // Custom resolution
      return conflict.remote;
    },
  },
  
  errors: {
    maxRetries: 5,
    retryDelay: (attempt) => Math.min(1000 * Math.pow(2, attempt), 60000),
  },
  
  observability: {
    enabled: true,
    metricsInterval: 30000,
    onMetrics: (metrics) => {
      console.log('Metrics:', metrics);
    },
  },
});
```

--------------------------------

### SyncEngine Methods

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Provides methods to control the lifecycle, trigger manual sync operations, and query the status of the synchronization engine.

```APIDOC
## SyncEngine Methods

### Lifecycle
- `await syncEngine.start()`
- `await syncEngine.stop()`
- `await syncEngine.pause()`
- `await syncEngine.resume()`

### Manual Sync
- `const result = await syncEngine.sync()`
- `await syncEngine.push()`
- `await syncEngine.pull()`
- `await syncEngine.syncTable('posts')`

### Status
- `const status = syncEngine.getStatus()`
- `const isOnline = syncEngine.isOnline()`
- `const isSyncing = syncEngine.isSyncing()`
- `const depth = await syncEngine.getQueueDepth()`

### Events
- `syncEngine.on('sync-complete', (result) => { ... });`

### Advanced
- `const health = await syncEngine.healthCheck()`
- `const deadLetters = await syncEngine.getDeadLetters()`
- `await syncEngine.retryDeadLetter(id)`
```

--------------------------------

### Manual Publishing - Update Version and Changelog

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/PUBLISHING.md

Use this command for manual updates to the package version and changelog, typically in emergency situations.

```bash
npm run version
```

--------------------------------

### SyncEngine Status and Information Methods

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Retrieve the current status and state of the sync engine. Useful for monitoring and debugging.

```typescript
// Status
const status = syncEngine.getStatus();
const isOnline = syncEngine.isOnline();
const isSyncing = syncEngine.isSyncing();
const depth = await syncEngine.getQueueDepth();
```

--------------------------------

### Push Changes to Fork

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Push your feature branch to your forked repository on GitHub.

```bash
git push origin feature/your-feature-name
```

--------------------------------

### SyncEngine Manual Sync Methods

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Manually trigger synchronization processes. These methods allow for on-demand pushing, pulling, or syncing specific tables.

```typescript
// Manual sync
const result = await syncEngine.sync();
await syncEngine.push();
await syncEngine.pull();
await syncEngine.syncTable('posts');
```

--------------------------------

### Lint Code

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Check the code for style and potential errors using ESLint.

```bash
npm run lint
```

--------------------------------

### Commit Changes

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Commit your changes with a descriptive message summarizing the modifications.

```bash
git commit -m "Description of your changes"
```

--------------------------------

### SyncEngine Event Handling

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Subscribe to various sync events to react to different stages of the synchronization process. This allows for custom logging or UI updates.

```typescript
// Events
syncEngine.on('sync-complete', (result) => {
  console.log('Synced!', result);
});
```

--------------------------------

### SyncEngine Advanced Methods

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Access advanced functionalities like health checks, managing dead-lettered items, and retrying failed operations.

```typescript
// Advanced
const health = await syncEngine.healthCheck();
const deadLetters = await syncEngine.getDeadLetters();
await syncEngine.retryDeadLetter(id);
```

--------------------------------

### Typecheck Code

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/CONTRIBUTING.md

Verify the TypeScript types throughout the project.

```bash
npm run typecheck
```

--------------------------------

### Sync Events

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/README.md

Listens for various events emitted by the synchronization engine to track sync progress, errors, and network status changes.

```APIDOC
## Events

- `sync-start` - Sync started
- `sync-complete` - Sync completed
- `sync-error` - Sync failed
- `push-start` - Push started
- `push-complete` - Push completed
- `push-error` - Push failed
- `pull-start` - Pull started
- `pull-complete` - Pull completed
- `pull-error` - Pull failed
- `conflict` - Conflict detected
- `online` - Network online
- `offline` - Network offline
- `metrics` - Metrics update
```

--------------------------------

### Controlling Table-Specific Synchronization

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/examples/basic-usage.md

Manage synchronization at the table level by pausing, resuming, or syncing specific tables.

```typescript
// Pause specific table
await syncEngine.pauseTable('posts');

// Resume specific table
await syncEngine.resumeTable('posts');

// Sync specific table only
await syncEngine.syncTable('posts');
```

--------------------------------

### Custom Conflict Resolution Policy

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/examples/basic-usage.md

Implement a custom conflict resolution policy by defining the `onConflict` function. This allows for specific merge logic when conflicts arise.

```typescript
startSync(db, {
  // ... other config
  conflicts: {
    policy: 'custom',
    onConflict: async (conflict) => {
      const { table, key, local, remote } = conflict;
      
      // Custom merge logic
      return {
        ...remote,
        title: local.title, // Keep local title
        content: remote.content // Use server content
      };
    }
  }
});
```

--------------------------------

### Monitoring Sync Health and Dead Letters

Source: https://github.com/abdussamadbello/dexie-sync-kit/blob/main/examples/basic-usage.md

Check the health of the synchronization process and retrieve items that failed to sync. Failed items can be retried.

```typescript
// Health check
const health = await syncEngine.healthCheck();
if (!health.healthy) {
  console.warn('Sync issues:', health.issues);
}

// Dead letter queue
const deadLetters = await syncEngine.getDeadLetters();
console.log('Failed items:', deadLetters);

// Retry failed items
for (const item of deadLetters) {
  await syncEngine.retryDeadLetter(item.id);
}
```

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