Deno 1.0 has finally been released. Billed as Node.js creator Ryan Dahl's "second attempt," it fixes the ten design regrets of Node.js. Now that 1.0 is out, let's seriously evaluate whether it's actually suitable for use in projects.

Deno's Core Selling Points

// 1. 安全：默认沙箱，需要显式授权
// 运行这个脚本会报错
const text = await Deno.readTextFile('/etc/hosts');
// error: Uncaught PermissionDenied

// 需要 --allow-read
deno run --allow-read script.ts

// 2. TypeScript 原生支持
interface User {
  name: string;
  age: number;
}

function greet(user: User): string {
  return `你好 ${user.name}，你 ${user.age} 岁了`;
}

console.log(greet({ name: '张三', age: 28 }));
// 直接运行，不需要 tsconfig.json
// deno run greet.ts

// 3. 标准库
import { serve } from 'https://deno.land/std@0.50.0/http/server.ts';
import { readJson } from 'https://deno.land/std@0.50.0/fs/read_json.ts';

Detailed Comparison with Node.js

| 特性         | Node.js              | Deno                 |
|-------------|----------------------|----------------------|
| 语言         | JavaScript           | TypeScript 原生      |
| 模块系统     | CommonJS + node_modules | ES Modules + URL  |
| 包管理       | npm / yarn           | URL 直接导入         |
| 安全模型     | 无限制               | 沙箱 + 显式授权       |
| 异步         | Callback → Promise   | 原生 async/await     |
| 标准库       | 无（依赖 npm）        | 内置标准库           |
| 工具链       | 需要额外配置          | 内置 test/lint/format |
| TypeScript   | 需要 ts-node         | 原生支持             |

Built-in Toolchain

# 测试
deno test

# 代码检查
deno lint

# 格式化
deno fmt

# 文档生成
deno doc

# 依赖树
deno info script.ts

// Deno.test 内置测试框架
Deno.test('加法测试', () => {
  const result = 1 + 2;
  if (result !== 3) {
    throw new Error('1 + 2 应该等于 3');
  }
});

Deno.test('异步测试', async () => {
  const response = await fetch('https://httpbin.org/get');
  const data = await response.json();
  console.assert(data.url === 'https://httpbin.org/get');
});

Building a Small Service

// server.ts
import { Application, Router } from 'https://deno.land/x/oak@v5.0.0/mod.ts';

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

interface Todo {
  id: number;
  title: string;
  completed: boolean;
}

let todos: Todo[] = [];
let nextId = 1;

router
  .get('/api/todos', (ctx) => {
    ctx.response.body = todos;
  })
  .post('/api/todos', async (ctx) => {
    const body = await ctx.request.body();
    const todo: Todo = {
      id: nextId++,
      title: body.value.title,
      completed: false,
    };
    todos.push(todo);
    ctx.response.status = 201;
    ctx.response.body = todo;
  })
  .delete('/api/todos/:id', (ctx) => {
    const id = Number(ctx.params.id);
    todos = todos.filter(t => t.id !== id);
    ctx.response.status = 204;
  });

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

console.log('服务器运行在 http://localhost:8000');
await app.listen({ port: 8000 });

deno run --allow-net server.ts

Practical Issues Today

1. 生态太小：npm 有 130 万个包，Deno 的第三方模块很少
2. 企业支持：没有大公司在生产环境使用
3. 兼容性：很多 npm 包无法直接使用
4. IDE 支持：VSCode 插件还在早期
5. 部署方案：没有 PM2 这样的进程管理
6. 调试：Chrome DevTools 支持有，但体验不如 Node.js

When Deno Is Worth Considering

适合：
- 个人工具脚本（替代 Python/Shell）
- 小型 API 服务
- 技术预研和学习
- CLI 工具

暂时不适合：
- 企业级项目
- 需要大量 npm 依赖的项目
- 性能关键的后端服务
- 需要 C++ addon 的项目

Summary

• Deno 1.0 is genuinely better than Node.js in terms of security and developer experience.
• It ships TypeScript, testing, linting, and formatting out of the box.
• URL imports do away with node_modules, but they also introduce version-management headaches.
• Its ecosystem is the biggest weakness; npm's ecosystem can't be caught up to in just a year or two.
• In 2020 you can use it for utility scripts, but stick with Node.js for production projects.