Express, Fastify หรือ NestJS: ติดตั้งและลอง API รายการงาน

node --version
npm --version

mkdir express-demo
cd express-demo
npm init -y
npm pkg set type=module 'scripts.start=node server.mjs'
npm install --save-exact express@5.3.0

import express from 'express';
const app = express();
app.use(express.json({limit: '1kb'}));
const tasks = [];
function titleOf(body) {
  if (!body || typeof body !== 'object' || Array.isArray(body) ||
      Object.keys(body).some(key => key !== 'title') || typeof body.title !== 'string') return null;
  const title = body.title.trim();
  return [...title].length >= 1 && [...title].length <= 80 ? title : null;
}
app.get('/tasks', (_req, res) => res.json(tasks));
app.get('/tasks/:id', (req, res) => {
  const task = /^[1-9]\d*$/.test(req.params.id) && tasks.find(t => t.id === Number(req.params.id));
  return task ? res.json(task) : res.status(404).json({error: 'Task not found'});
});
app.post('/tasks', (req, res) => {
  const title = titleOf(req.body);
  if (title === null) return res.status(400).json({error: 'Send only title, 1–80 code points after trim'});
  const task = {id: tasks.length + 1, title};
  tasks.push(task);
  res.status(201).json(task);
});
app.use((err, _req, res, _next) => {
  const status = [400, 413].includes(err.status) ? err.status : 500;
  res.status(status).json({error: status === 500 ? 'Internal error' : 'Invalid JSON request'});
});
app.listen(Number(process.env.PORT || 3101), '127.0.0.1');

mkdir fastify-demo
cd fastify-demo
npm init -y
npm pkg set type=module 'scripts.start=node server.mjs'
npm install --save-exact fastify@5.12.7

import Fastify from 'fastify';
const app = Fastify({bodyLimit: 1024, ajv: {customOptions: {coerceTypes: false, removeAdditional: false}}});
const tasks = [];
app.get('/tasks', async () => tasks);
app.get('/tasks/:id', async (req, reply) => {
  const task = /^[1-9]\d*$/.test(req.params.id) && tasks.find(t => t.id === Number(req.params.id));
  return task || reply.code(404).send({error: 'Task not found'});
});
app.post('/tasks', {preValidation: async req => {
  if (typeof req.body?.title === 'string') req.body.title = req.body.title.trim();
}, schema: {body: {
  type: 'object', required: ['title'], additionalProperties: false,
  properties: {title: {type: 'string', minLength: 1, maxLength: 80}}
}}}, async (req, reply) => {
  const title = req.body.title.trim();
  if (!title) return reply.code(400).send({error: 'Title must not be blank'});
  const task = {id: tasks.length + 1, title};
  tasks.push(task);
  return reply.code(201).send(task);
});
await app.listen({port: Number(process.env.PORT || 3102), host: '127.0.0.1'});

mkdir nest-demo
cd nest-demo
npm init -y
npm pkg set type=commonjs 'scripts.build=tsc' 'scripts.start=node dist/main.js'
npm install --save-exact @nestjs/common@12.1.3 @nestjs/core@12.1.3 @nestjs/platform-express@12.1.3 reflect-metadata rxjs
npm install --save-dev --save-exact typescript@6.0.3 @types/node@22

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "NodeNext",
    "moduleResolution": "NodeNext",
    "strict": true,
    "skipLibCheck": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "outDir": "dist",
    "types": [
      "node"
    ]
  },
  "include": [
    "main.ts"
  ]
}

import 'reflect-metadata';
import {BadRequestException, Body, Controller, Get, Injectable, Module, NotFoundException, Param, Post} from '@nestjs/common';
import {NestFactory} from '@nestjs/core';

type Task = {id: number; title: string};
function titleOf(body: unknown): string {
  if (!body || typeof body !== 'object' || Array.isArray(body) ||
      Object.keys(body).some(key => key !== 'title') ||
      !('title' in body) || typeof body.title !== 'string') throw new BadRequestException('Send only title');
  const title = body.title.trim();
  if ([...title].length < 1 || [...title].length > 80) throw new BadRequestException('Title must contain 1–80 code points');
  return title;
}
@Injectable()
class TasksService {
  private readonly tasks: Task[] = [];
  list() { return this.tasks; }
  find(id: string) {
    const task = /^[1-9]\d*$/.test(id) && this.tasks.find(t => t.id === Number(id));
    if (!task) throw new NotFoundException('Task not found');
    return task;
  }
  create(title: string) {
    const task = {id: this.tasks.length + 1, title};
    this.tasks.push(task);
    return task;
  }
}
@Controller('tasks')
class TasksController {
  constructor(private readonly tasks: TasksService) {}
  @Get() list() { return this.tasks.list(); }
  @Get(':id') find(@Param('id') id: string) { return this.tasks.find(id); }
  @Post() create(@Body() body: unknown) { return this.tasks.create(titleOf(body)); }
}
@Module({controllers: [TasksController], providers: [TasksService]})
class AppModule {}
async function main() {
  const app = await NestFactory.create(AppModule);
  await app.listen(Number(process.env.PORT || 3103), '127.0.0.1');
}
void main();

npm run build
npm start

curl -i http://127.0.0.1:3101/tasks
curl -i -X POST http://127.0.0.1:3101/tasks -H 'Content-Type: application/json' -d '{"title":"เรียน backend"}'
curl -i http://127.0.0.1:3101/tasks/1

import {test} from 'node:test';
import assert from 'node:assert/strict';
const base = `http://127.0.0.1:${process.env.PORT || 3101}`;
test('tasks API on a freshly started server', async () => {
  const send = body => fetch(base + '/tasks', {method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify(body)});
  assert.deepEqual(await (await fetch(base + '/tasks')).json(), []);
  const created = await send({title: '  เรียน backend  '});
  assert.equal(created.status, 201);
  assert.deepEqual(await created.json(), {id: 1, title: 'เรียน backend'});
  assert.deepEqual(await (await fetch(base + '/tasks/1')).json(), {id: 1, title: 'เรียน backend'});
  assert.equal((await (await fetch(base + '/tasks')).json()).length, 1);
  for (const body of [{}, {title: 123}, {title: '  '}, {title: 'x', extra: true}, [], {title: '😀'.repeat(81)}]) assert.equal((await send(body)).status, 400);
  assert.equal((await send({title: '😀'.repeat(80)})).status, 201);
  assert.equal((await fetch(base + '/tasks', {method: 'POST', headers: {'Content-Type': 'application/json'}, body: '{broken'})).status, 400);
  for (const id of ['999', '0', 'abc']) assert.equal((await fetch(base + '/tasks/' + id)).status, 404);
});

PORT=3101 node --test smoke-test.mjs
# Fastify: PORT=3102 node --test smoke-test.mjs
# NestJS: PORT=3103 node --test smoke-test.mjs