Form Validation

const formSchema = new SchemaBuilder()
  .object()
  .properties({
    username: (s) =>
      s
        .string()
        .minLength(3)
        .maxLength(20)
        .pattern("^[a-zA-Z0-9_]+$")
        .title("Username")
        .description("Alphanumeric characters and underscores only")
        .errorMessage({
          minLength: "Username must be at least 3 characters",
          maxLength: "Username cannot exceed 20 characters",
          pattern:
            "Username can only contain letters, numbers, and underscores",
        }),
    email: (s) =>
      s
        .string()
        .format("email")
        .title("Email Address")
        .errorMessage("Please enter a valid email address"),
    password: (s) =>
      s
        .string()
        .minLength(8)
        .pattern("^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)")
        .title("Password")
        .description("Must contain uppercase, lowercase, and number")
        .errorMessage({
          minLength: "Password must be at least 8 characters",
          pattern: "Password must contain uppercase, lowercase, and a number",
        }),
    confirmPassword: (s) =>
      s
        .string()
        .const({ $data: "1/password" })
        .title("Confirm Password")
        .errorMessage("Passwords do not match"),
    age: (s) =>
      s.integer().minimum(13).maximum(120).title("Age").errorMessage({
        minimum: "You must be at least 13 years old",
        maximum: "Please enter a valid age",
      }),
    country: (s) => s.string().enum(["US", "UK", "CA", "AU"]).title("Country"),
    agreedToTerms: (s) =>
      s
        .boolean()
        .const(true)
        .title("I agree to the terms and conditions")
        .errorMessage("You must agree to the terms and conditions"),
  })
  .required([
    "username",
    "email",
    "password",
    "confirmPassword",
    "age",
    "agreedToTerms",
  ])
  .if((s) => s.object().properties({ country: (s) => s.const("US") }))
  .then((s) =>
    s
      .object()
      .properties({
        state: (s) =>
          s
            .string()
            .pattern("^[A-Z]{2}$")
            .title("State")
            .errorMessage("Please enter a valid 2-letter state code"),
      })
      .required(["state"]),
  )
  .build();