Examples

Zelt includes example applications demonstrating real-world usage patterns.

Drizzle Todo

A simple Todo API using Drizzle ORM with SQLite.

Location: examples/drizzle-todo

Features

• CRUD operations with Drizzle ORM
• Request validation with Valibot
• SQLite database with better-sqlite3
• Disposable pattern for cleanup

Running

cd examples/drizzle-todo
pnpm install
pnpm dev

Key Code

Controller with validation:

import { Controller, Get, Post, inject, pathParam, validated } from '@zeltjs/core';
import * as v from 'valibot';

const CreateTodoBody = v.object({
  title: v.pipe(v.string(), v.minLength(1)),
});

@Controller('/todos')
class TodoController {
  constructor(private todoService = inject(TodoService)) {}

  @Get('/')
  findAll() {
    return this.todoService.findAll();
  }

  @Post('/')
  create(body = validated(CreateTodoBody), res = response()) {
    const todo = this.todoService.create({ title: body.title });
    return res.json(todo, 201);
  }
}

Drizzle service with Disposable:

import { Injectable } from '@zeltjs/core';
import type { Disposable } from '@zeltjs/core';
import Database from 'better-sqlite3';
import { drizzle } from 'drizzle-orm/better-sqlite3';

@Injectable()
class DrizzleService implements Disposable {
  private sqlite: Database.Database;
  readonly db;

  constructor() {
    this.sqlite = new Database('./data/todo.db');
    this.db = drizzle(this.sqlite, { schema });
  }

  dispose() {
    this.sqlite.close();
  }
}

API Endpoints

Method	Path	Description
GET	/todos	List all todos
GET	/todos/:id	Get a todo by ID
POST	/todos	Create a new todo
PATCH	/todos/:id	Update a todo
DELETE	/todos/:id	Delete a todo

---

Workers URL Shortener

A URL shortener running on Cloudflare Workers with KV storage.

Location: examples/workers-url-shortener

Features

• Cloudflare Workers deployment
• KV storage for persistence
• URL validation
• Hit counter for analytics

Running

cd examples/workers-url-shortener
pnpm install
pnpm dev

Key Code

Worker entry point:

import { app } from './app';

export default {
  fetch: app.fetch,
};

Controller with KV access:

import { Controller, Get, Post, inject, pathParam, requestContext, validated } from '@zeltjs/core';
import * as v from 'valibot';

const ShortenBody = v.object({
  url: v.pipe(v.string(), v.url()),
});

@Controller('/')
class UrlController {
  constructor(private kv = inject(KVService)) {}

  @Post('/shorten')
  async shorten(body = validated(ShortenBody), res = response(), ctx = requestContext()) {
    const code = generateCode();
    await this.kv.set(ctx, code, { url: body.url, createdAt: Date.now(), hits: 0 });
    return res.json({ code, shortUrl: `/${code}` }, 201);
  }

  @Get('/:code')
  async redirect(code = pathParam('code'), res = response(), ctx = requestContext()) {
    const record = await this.kv.get(ctx, code);
    if (!record) throw new HTTPException(404, { message: 'URL not found' });
    await this.kv.incrementHits(ctx, code);
    return res.redirect(record.url, 302);
  }
}

KV service:

import { Injectable } from '@zeltjs/core';

@Injectable()
class KVService {
  async get(c: RequestContext, code: string) {
    return c.env.URLS.get(`url:${code}`, 'json');
  }

  async set(c: RequestContext, code: string, record: UrlRecord) {
    await c.env.URLS.put(`url:${code}`, JSON.stringify(record));
  }
}

API Endpoints

Method	Path	Description
POST	/shorten	Create a short URL
GET	/:code	Redirect to original URL
GET	/stats/:code	Get URL statistics

wrangler.toml

name = "url-shortener"
main = "src/worker.ts"
compatibility_date = "2024-01-01"

[[kv_namespaces]]
binding = "URLS"
id = "your-kv-namespace-id"

---

Running Examples

All examples are in the examples/ directory. Each has its own package.json:

# Install dependencies for an example
cd examples/<example-name>
pnpm install

# Run in development mode
pnpm dev

# Run tests (if available)
pnpm test