type ValidationMessage = string;

type ValidationSuccess = [];
type ValidationErr = [ValidationMessage, ...ValidationMessage[]];

export type ValidationInfo = ValidationSuccess | ValidationErr;

export type Validator<T = any> = (_: T) => ValidationInfo;

export const isValidationSuccess = (info: ValidationInfo): info is ValidationSuccess =>
  !info?.length;
export const isValidationErr = (info: ValidationInfo): info is ValidationErr =>
  Boolean(info?.length);

type Predicate<T = any> = (_: T) => boolean;

export const validator =
  <T = any>(predicate: Predicate<T>) =>
  (message: string): Validator<T> =>
  (_) =>
    predicate(_) ? [] : [message];