validate/in.go

package validate

var (
	ErrValueNotAllowed = NewError("not allowed")
)

// In validates that a value equals one of the allowed values.
func In[T comparable](allow ...T) func(T) error {
	return func(value T) error {
		for _, cmp := range allow {
			if cmp == value {
				return nil
			}
		}
		return ErrValueNotAllowed
	}
}

// NotIn validates that a value equals none of the disallowed values.
func NotIn[T comparable](disallow ...T) func(T) error {
	return func(value T) error {
		for _, cmp := range disallow {
			if cmp == value {
				return ErrValueNotAllowed
			}
		}
		return nil
	}
}