import { ValidatorFn, ValidationErrors } from '@angular/forms';
export type RevalidateFn = () => ValidationErrors | null;
export interface ValidationGroup {
    /**
     * Triggers validation when value was changed and return validation errors.
     */
    validate: ValidatorFn;
    /**
     * Just get current validation errors without trigger validation.
     */
    validationErrors: ValidatorFn;
    /**
     * Triggers validation when value was changed but returns null always.
     */
    link: ValidatorFn;
    /**
     * Can be used to full revalidation of validation group. F.e. when external data which was used for validation was changed.
     */
    revalidate: RevalidateFn;
}
export type ValidationGroupValidatorFn<T> = (formValue: T) => ValidationErrors | null;
export type Validator<T> = ValidationGroupValidatorFn<Partial<T>> | ValidationGroupValidatorFn<Partial<T>>[];
export type IsEqualComparer<T> = (previousFormValue: Partial<T>, formValue: Partial<T>) => boolean;
export interface ValidationGroupRevalidationOptions {
    onlySelf?: boolean;
    emitEvent?: boolean;
}
export interface ValidationGroupOptions<T> {
    validator: Validator<T>;
    revalidationOptions?: ValidationGroupRevalidationOptions;
    isEqualComparer?: IsEqualComparer<T>;
}
export type ValidationGroupInput<T> = Validator<T> | ValidationGroupOptions<T>;
export declare function createValidationGroup<T>(validatorOrOpts: ValidationGroupInput<T>): ValidationGroup;