import { EqualityCheck } from './types';
/**
 * Creates an equality check that accepts null and undefined values
 *
 * @param comparator comparator to be wrapped with the null check
 */
export declare const createNullableEqualityCheck: <T>(comparator: EqualityCheck<T>) => (value: T | null | undefined) => boolean;
/**
 * Creates an equality check that tests that the values of all the properties in an object
 * haven't changed.
 *
 * The comparison used for the value of the properties is passed to it as an argument.
 *
 * @param comparator the equality check to be run for each property
 */
export declare const createUniformObjectEqualityCheck: <T>(comparator: EqualityCheck<T[Extract<keyof T, string>]>) => () => (current: T) => boolean;
/**
 * Creates an equality check that tests that the items in an array
 * haven't changed.
 *
 * The comparison used for the individual items is passed to it as an argument.
 *
 * @param comparator the equality check to be run for each item
 */
export declare const createUniformArrayEqualityCheck: <T>(comparator: EqualityCheck<T>) => () => (current: T[]) => boolean;
/**
 * Creates an equality check that tests whether each property of the target object has changed.
 * Each property is tested with a different comparator, so that they can be of different types.
 *
 * The comparator are passed down to it as an object with the same keys as the target object, but
 * comparators for each property as values.
 *
 * @param comparators the object containing the equality checks to be run for each property
 */
export declare const createObjectWithKeySpecificEqualityCheck: <T>(comparators: { [K in keyof T]: EqualityCheck<T[K]>; }) => () => (current: T) => boolean;
/**
 * Creates an equality check that tests whether the value changed from null to defined or stayed the same
 *
 * If the value was not null before and it is not null currently, the comparison is done by the equality check
 * provided as an argument to this creator.
 *
 * This creator is useful to be able to make equality checkers for optional properties when you already have
 * an equality check for the underlying type.
 *
 * @param comparator the equality check to be run in case the value was defined before and now
 */
export declare const createOptionalValueEqualityCheck: <T>(comparator: EqualityCheck<T>) => () => (current: T | null | undefined) => boolean;