สร้าง API พร้อม Validation ด้วย Express.js + Zod

mkdir express-zod-workshop
cd express-zod-workshop
npm init -y

npm install express body-parser zod
npm install --save-dev typescript @types/node @types/express ts-node nodemon

npx tsc --init

import express from 'express';
import bodyParser from 'body-parser';
import userRouter from './routes/userRoutes';

const app = express();
const PORT = 3000;

app.use(bodyParser.json());
app.use('/api/user', userRouter);

app.listen(PORT, () => {
  console.log(`Server is running on http://localhost:${PORT}`);
});

import { z } from 'zod';

export const userRegistrationSchema = z.object({
  username: z.string().min(3, "Username must have at least 3 characters"),
  email: z.string().email("Invalid email address"),
  password: z.string().min(8, "Password must have at least 8 characters"),
});

export const userLoginSchema = z.object({
  username: z.string(),
  password: z.string().min(8, "Password must have at least 8 characters"),
});

import { z } from 'zod';

const stringSchema = z.string(); // ค่าเป็น string
const numberSchema = z.number(); // ค่าเป็น number
const booleanSchema = z.boolean(); // ค่าเป็น boolean
const dateSchema = z.date(); // ค่าเป็น Date object

const schema = z.string()
  .min(3, "Must be at least 3 characters") // ความยาวขั้นต่ำ
  .max(10, "Must be at most 10 characters") // ความยาวสูงสุด
  .email("Invalid email address") // ต้องเป็นอีเมล
  .url("Invalid URL"); // ต้องเป็น URL

const schema = z.number()
  .min(0, "Must be at least 0") // ค่าน้อยสุด
  .max(100, "Must be at most 100") // ค่าสูงสุด
  .int("Must be an integer"); // ต้องเป็นจำนวนเต็ม

const schema = z.array(z.string()); // อาร์เรย์ที่มี string
const schemaWithMinMax = z.array(z.number()).min(1).max(5); // อาร์เรย์ของ number ที่มี 1-5 รายการ

const schema = z.object({
  username: z.string().min(3),
  age: z.number().min(18),
  email: z.string().email(),
});

import { Request, Response, NextFunction } from 'express';
import { z, ZodError } from 'zod';

export function validateData(schema: z.ZodObject<any>) {
  return (req: Request, res: Response, next: NextFunction) => {
    try {
      schema.parse(req.body);
      next();
    } catch (error) {
      if (error instanceof ZodError) {
        const errorMessages = error.errors.map(err => ({
          path: err.path.join('.'),
          message: err.message,
        }));
        res.status(400).json({ error: "Invalid data", details: errorMessages });
      } else {
        res.status(500).json({ error: "Internal Server Error" });
      }
    }
  };
}

import express from 'express';
import { validateData } from '../middleware/validationMiddleware';
import { userRegistrationSchema, userLoginSchema } from '../schemas/userSchemas';

const userRouter = express.Router();

userRouter.post('/register', validateData(userRegistrationSchema), (req, res) => {
  res.json({ message: "User registered successfully!", data: req.body });
});

userRouter.post('/login', validateData(userLoginSchema), (req, res) => {
  res.json({ message: "User logged in successfully!", data: req.body });
});

export default userRouter;

npx ts-node-dev src/index.ts

{
  "username": "john",
  "email": "john@example.com",
  "password": "mypassword"
}