import { Operator, Filter as IFilter } from './query';
import { entity } from './entity';
import Key = entity.Key;
declare enum CompositeOperator {
    AND = "AND",
    OR = "OR"
}
export declare function and(filters: EntityFilter[]): CompositeFilter;
export declare function or(filters: EntityFilter[]): CompositeFilter;
/**
 * A Filter is a class that contains data for a filter that can be translated
 * into a proto when needed.
 *
 * @see {@link https://cloud.google.com/datastore/docs/concepts/queries#filters| Filters Reference}
 *
 */
export declare abstract class EntityFilter {
    /**
     * Gets the proto for the filter.
     *
     */
    abstract toProto(): any;
}
export type AllowedFilterValueType<T> = T extends '__key__' ? Key | Key[] : unknown;
/**
 * A PropertyFilter is a filter that gets applied to a query directly.
 *
 * @see {@link https://cloud.google.com/datastore/docs/concepts/queries#property_filters| Property filters Reference}
 *
 * @class
 */
export declare class PropertyFilter<T extends string> extends EntityFilter implements IFilter {
    name: T;
    op: Operator;
    val: AllowedFilterValueType<T>;
    /**
     * Build a Property Filter object.
     *
     * @param {string} Property
     * @param {Operator} operator
     * @param {any} val
     */
    constructor(name: T, op: Operator, val: AllowedFilterValueType<T>);
    /**
     * Gets the proto for the filter.
     *
     */
    toProto(): any;
}
/**
 * A CompositeFilter is a filter that combines other filters and applies that
 * combination to a query.
 *
 * @see {@link https://cloud.google.com/datastore/docs/concepts/queries#composite_filters| Composite filters Reference}
 *
 * @class
 */
declare class CompositeFilter extends EntityFilter {
    filters: EntityFilter[];
    op: string;
    /**
     * Build a Composite Filter object.
     *
     * @param {EntityFilter[]} filters
     */
    constructor(filters: EntityFilter[], op: CompositeOperator);
    /**
     * Gets the proto for the filter.
     *
     */
    toProto(): any;
}
export declare function isFilter(filter: any): filter is EntityFilter;
export {};