Heavy Validation

export interface User {
  id: number;
  username: string;
  email: string;
  profile: {
    firstName: string;
    lastName: string;
    displayName: string;
    bio?: string;
    avatarUrl?: string;
    dateOfBirth: Date;
  };
  role: "admin" | "user" | "guest" | "moderator";
  status: "active" | "suspended" | "pending_verification" | "deactivated";
  address: Address;
  paymentMethods: PaymentMethod[]; // Discriminated union
  preferences: UserPreferences;
  createdAt: Date;
  updatedAt: Date;
  lastLoginAt?: Date;
  tags: string[];
}

// ### mion ###
// the received user by the route is already validated and deserialized
// all Date fields are already JS Date objects (not strings from JSON.parse)
export const routes: Routes = {
  updateUser: (ctx, user: User): User => {
    user.updatedAt = new Date();
    user.lastLoginAt = new Date();
    user.profile.displayName = `${user.profile.firstName} ${user.profile.lastName.charAt(0)}.`;
    return user;
  },
};

// ### Other frameworks (Express, Fastify, Hono, etc.) ###
// Use Zod schemas for validation and date coercion
const UserSchema = z.object({
  id: z.number(),
  username: z.string(),
  // ... full schema with nested objects, discriminated unions, etc.
  createdAt: z.coerce.date(),
  updatedAt: z.coerce.date(),
  // ...
});

app.post("/updateUser", function (req, res) {
  const user = UserSchema.parse(req.body); // Validates + deserializes dates
  user.updatedAt = new Date();
  user.lastLoginAt = new Date();
  user.profile.displayName = `${user.profile.firstName} ${user.profile.lastName.charAt(0)}.`;
  res.json(user);
});