export type Specification<T> = (candidate: T) => boolean;
export declare function and<T>(...specs: Specification<T>[]): Specification<T>;
export declare function or<T>(...specs: Specification<T>[]): Specification<T>;
export declare function not<T>(spec: Specification<T>): Specification<T>;
export declare function alwaysTrue<T>(): Specification<T>;
export declare function alwaysFalse<T>(): Specification<T>;
export declare function propEquals<T, K extends keyof T = keyof T>(propertyName: K, expectedValue: T[K]): Specification<T>;
export declare function propIn<T, K extends keyof T = keyof T>(propertyName: K, values: T[K][]): Specification<T>;
export declare function dateRange<T>(propertyName: keyof T, range: {
    start?: Date;
    end?: Date;
}): Specification<T>;
export declare function numericRange<T>(propertyName: keyof T, range: {
    min?: number;
    max?: number;
}): Specification<T>;
export declare function propTruthy<T>(propertyName: keyof T): Specification<T>;
export declare function propFalsy<T>(propertyName: keyof T): Specification<T>;
export declare function propNullish<T>(propertyName: keyof T): Specification<T>;
export declare function propNotNullish<T>(propertyName: keyof T): Specification<T>;
export declare function propContains<T, V>(propertyName: keyof T, value: V): Specification<T>;
export declare function spec<T>(predicate: (candidate: T) => boolean): Specification<T>;
export declare function filterBy<T>(items: T[], specification: Specification<T>): T[];
export declare function findBy<T>(items: T[], specification: Specification<T>): T | undefined;
export declare function countBy<T>(items: T[], specification: Specification<T>): number;
export declare function someBy<T>(items: T[], specification: Specification<T>): boolean;
export declare function everyBy<T>(items: T[], specification: Specification<T>): boolean;