What are popular libraries and tools in Deno's ecosystem?

Deno's ecosystem, though relatively young, is developing rapidly and offers a wealth of third-party libraries and tools. Understanding Deno's ecosystem helps developers better leverage existing resources.

Ecosystem Overview

Deno's ecosystem mainly consists of the following parts:

1. deno.land/x - Third-party module registry
2. deno.land/std - Official standard library
3. nest.land - Another popular module registry
4. Deno Deploy - Official edge computing platform
5. Community tools and frameworks - Various development tools and frameworks

Popular Third-party Libraries

1. Web Frameworks

Oak

typescript
import { Application, Router } from "https://deno.land/x/oak@v12.6.1/mod.ts";

const app = new Application();
const router = new Router();

router.get("/", (ctx) => {
  ctx.response.body = "Hello, Oak!";
});

router.get("/users/:id", (ctx) => {
  const { id } = ctx.params;
  ctx.response.body = { id, name: `User ${id}` };
});

app.use(router.routes());
app.use(router.allowedMethods());

await app.listen({ port: 8000 });

Fresh

typescript
import { Fresh } from "https://deno.land/x/fresh@1.4.0/server.ts";
import { handler } from "./routes/index.tsx";

const app = new Fresh();

app.get("/", handler);

await app.listen({ port: 8000 });

Hono

typescript
import { Hono } from "https://deno.land/x/hono@v3.11.0/mod.ts";

const app = new Hono();

app.get("/", (c) => c.text("Hello, Hono!"));

app.get("/users/:id", (c) => {
  const id = c.req.param("id");
  return c.json({ id, name: `User ${id}` });
});

Deno.serve(app.fetch);

2. Database Clients

PostgreSQL (postgres)

typescript
import { Client } from "https://deno.land/x/postgres@v0.17.0/mod.ts";

const client = new Client({
  user: "user",
  database: "database",
  hostname: "localhost",
  port: 5432,
  password: "password",
});

await client.connect();

const result = await client.queryArray("SELECT * FROM users");
console.log(result.rows);

await client.end();

MySQL (mysql)

typescript
import { Client } from "https://deno.land/x/mysql@v2.12.0/mod.ts";

const client = await new Client().connect({
  hostname: "127.0.0.1",
  username: "root",
  password: "password",
  db: "test",
});

const users = await client.query("SELECT * FROM users");
console.log(users);

await client.close();

MongoDB (mongo)

typescript
import { MongoClient } from "https://deno.land/x/mongo@v0.31.0/mod.ts";

const client = new MongoClient();
await client.connect("mongodb://localhost:27017");

const db = client.database("test");
const users = db.collection<User>("users");

const user = await users.findOne({ name: "John" });
console.log(user);

await client.close();

Redis (redis)

typescript
import { connect } from "https://deno.land/x/redis@v0.31.0/mod.ts";

const redis = await connect({
  hostname: "127.0.0.1",
  port: 6379,
});

await redis.set("key", "value");
const value = await redis.get("key");
console.log(value);

await redis.close();

3. ORM and Query Builders

DenoDB

typescript
import { Database } from "https://deno.land/x/denodb@v1.0.0/mod.ts";

const db = new Database("postgres", {
  host: "127.0.0.1",
  username: "user",
  password: "password",
  database: "test",
});

class User extends Model {
  static fields = {
    id: { primaryKey: true, autoIncrement: true },
    name: { type: VARCHAR },
    email: { type: VARCHAR, unique: true },
  };
}

db.link([User]);
await db.sync();

const user = await User.create({ name: "John", email: "john@example.com" });
console.log(user);

Drizzle ORM

typescript
import { drizzle } from "https://deno.land/x/drizzle@v0.5.0/mod.ts";
import { pgTable, serial, text, varchar } from "https://deno.land/x/drizzle@v0.5.0/pg-core/mod.ts";

const users = pgTable("users", {
  id: serial("id").primaryKey(),
  name: text("name").notNull(),
  email: varchar("email", { length: 255 }).notNull().unique(),
});

const db = drizzle("postgresql://user:password@localhost:5432/test");

const user = await db.insert(users).values({
  name: "John",
  email: "john@example.com",
}).returning().get();

console.log(user);

4. Authentication and Authorization

JWT (djwt)

typescript
import { create, verify, getNumericDate } from "https://deno.land/x/djwt@v3.0.1/mod.ts";

const key = await crypto.subtle.generateKey(
  { name: "HMAC", hash: "SHA-256" },
  true,
  ["sign", "verify"]
);

const payload = {
  iss: "my-app",
  exp: getNumericDate(60 * 60), // 1 hour
  data: { userId: 123 },
};

const token = await create({ alg: "HS256", typ: "JWT" }, payload, key);
console.log("Token:", token);

const verified = await verify(token, key);
console.log("Verified:", verified);

OAuth (oauth2_client)

typescript
import { OAuth2Client } from "https://deno.land/x/oauth2_client@v1.0.2/mod.ts";

const oauth2Client = new OAuth2Client({
  clientId: "your-client-id",
  clientSecret: "your-client-secret",
  authorizationEndpointUri: "https://github.com/login/oauth/authorize",
  tokenUri: "https://github.com/login/oauth/access_token",
});

const authUrl = oauth2Client.code.getAuthorizationUri({
  redirectUri: "http://localhost:8000/callback",
  scope: "read:user",
});

console.log("Visit:", authUrl);

5. Utility Libraries

Lodash (lodash)

typescript
import _ from "https://deno.land/x/lodash@4.17.19-es/mod.ts";

const users = [
  { name: "John", age: 30 },
  { name: "Jane", age: 25 },
];

const sorted = _.orderBy(users, ["age"], ["asc"]);
console.log(sorted);

const names = _.map(users, "name");
console.log(names);

Date-fns (date_fns)

typescript
import { format, addDays, isAfter } from "https://deno.land/x/date_fns@v2.29.3/mod.ts";

const now = new Date();
const future = addDays(now, 7);

console.log(format(now, "yyyy-MM-dd"));
console.log(format(future, "yyyy-MM-dd"));
console.log(isAfter(future, now));

Zod (zod)

typescript
import { z } from "https://deno.land/x/zod@v3.21.4/mod.ts";

const UserSchema = z.object({
  id: z.number(),
  name: z.string().min(2),
  email: z.string().email(),
  age: z.number().min(0).max(120),
});

const userData = {
  id: 1,
  name: "John",
  email: "john@example.com",
  age: 30,
};

const user = UserSchema.parse(userData);
console.log(user);

6. Testing Tools

Supabase (supabase)

typescript
import { createClient } from "https://deno.land/x/supabase@2.0.0/mod.ts";

const supabase = createClient(
  "your-project-url",
  "your-anon-key"
);

const { data, error } = await supabase
  .from("users")
  .select("*")
  .eq("id", 1);

console.log(data);

Development Tools

1. Code Formatting

Deno has built-in formatting tools:

bash
deno fmt .

2. Code Linting

bash
deno lint .

3. Documentation Generation

bash
deno doc --html --output=./docs ./src

4. Dependency Check

bash
deno info

Package Management Tools

1. Denoify

Convert Node.js packages to Deno-compatible packages:

bash
denoify

2. Deno 2 NPM (d2n)

Convert npm packages to Deno modules:

bash
d2n express

3. Import Map Generator

Automatically generate import map:

bash
deno run --allow-read --allow-write https://deno.land/x/import_map_generator/main.ts

Deployment Platforms

1. Deno Deploy

Official edge computing platform:

typescript
// main.ts
import { serve } from "https://deno.land/std@0.208.0/http/server.ts";

serve((req) => {
  return new Response("Hello from Deno Deploy!");
});

2. Vercel

Supports Deno deployment:

json
{
  "builds": [
    {
      "src": "main.ts",
      "use": "@vercel/deno"
    }
  ]
}

3. Railway

Supports Deno deployment:

toml
[build]
builder = "NIXPACKS"

[deploy]
startCommand = "deno run --allow-net main.ts"

Community Resources

1. Official Resources

• Official Website: https://deno.land
• Documentation: https://deno.land/manual
• Standard Library: https://deno.land/std
• Third-party Libraries: https://deno.land/x

2. Community Forums

• GitHub Discussions: https://github.com/denoland/deno/discussions
• Discord: https://discord.gg/deno
• Twitter: @deno_land

3. Learning Resources

• Deno by Example: https://examples.deno.land
• Deno Tutorial: https://deno-tutorial.com
• Awesome Deno: https://github.com/denolib/awesome-deno

Best Practices

1. Choosing the Right Library

• Prioritize using standard library
• Choose actively maintained third-party libraries
• Check library documentation and examples
• Check library update frequency

2. Version Management

typescript
// Specify specific version
import { serve } from "https://deno.land/std@0.208.0/http/server.ts";
import { Application } from "https://deno.land/x/oak@v12.6.1/mod.ts";

3. Security

• Check library security
• Use principle of least privilege
• Regularly update dependencies

4. Performance

• Choose performance-optimized libraries
• Avoid unnecessary dependencies
• Use caching strategies

Migration Guide

1. Migrating from Node.js

typescript
// Node.js
const express = require('express');
const app = express();

// Deno
import { Application } from "https://deno.land/x/oak@v12.6.1/mod.ts";
const app = new Application();

2. Using Compatibility Layer

typescript
import { polyfill } from "https://deno.land/x/node_polyfills@v0.1.48/main.ts";

polyfill();

// Now you can use Node.js APIs
const fs = require('fs');

Future Development

Deno's ecosystem is developing rapidly, here are some trends worth watching:

1. More third-party libraries: Ecosystem continues to expand
2. Better tool support: Development tools continuously improving
3. Enterprise features: More enterprise-level features
4. Performance optimization: Continuous performance improvements
5. Cross-platform support: Better cross-platform compatibility

Deno's ecosystem, though young, is developing rapidly and offers rich resources and tools. By reasonably leveraging these resources, developers can build applications more efficiently.