npm install valibot

import * as v from "valibot";

const UserSchema = v.object({
  name: v.pipe(v.string(), v.minLength(2), v.maxLength(50)),
  email: v.pipe(v.string(), v.email()),
  age: v.pipe(v.number(), v.minValue(0), v.maxValue(120)),
  role: v.picklist(["admin", "user", "guest"]),
});

type User = v.InferOutput<typeof UserSchema>;

const result = v.safeParse(UserSchema, {
  name: "Sarah",
  email: "sarah@example.com",
  age: 28,
  role: "admin",
});

if (result.success) {
  console.log(result.output); // Typed as User
} else {
  console.log(result.issues); // Detailed validation errors
}

import { useForm } from "react-hook-form";
import { valibotResolver } from "@hookform/resolvers/valibot";
import * as v from "valibot";

const SignupSchema = v.object({
  email: v.pipe(v.string(), v.email("Enter a valid email")),
  password: v.pipe(v.string(), v.minLength(8, "Password must be at least 8 characters")),
});

type SignupForm = v.InferOutput<typeof SignupSchema>;

export function SignupForm() {
  const { register, handleSubmit, formState: { errors } } = useForm<SignupForm>({
    resolver: valibotResolver(SignupSchema),
  });

  return (
    <form onSubmit={handleSubmit((data) => console.log(data))}>
      <input {...register("email")} />
      {errors.email && <p>{errors.email.message}</p>}
      <input type="password" {...register("password")} />
      {errors.password && <p>{errors.password.message}</p>}
      <button type="submit">Sign up</button>
    </form>
  );
}

import * as v from "valibot";

const CreatePostSchema = v.object({
  title: v.pipe(v.string(), v.minLength(1), v.maxLength(200)),
  content: v.pipe(v.string(), v.minLength(1)),
  tags: v.array(v.string()),
});

export async function POST(request: Request) {
  const body = await request.json();
  const result = v.safeParse(CreatePostSchema, body);

  if (!result.success) {
    return Response.json({ errors: result.issues }, { status: 400 });
  }

  // result.output is fully typed
  const post = await createPost(result.output);
  return Response.json(post);
}