import { Observable, Subject } from 'rxjs';
import { NonPrimitiveUnitBase } from './abstract-non-primitive-unit-base';
import { DictUnitEvents, DictValue, KOf, UnitConfig } from '../models';
/**
 * DictUnit is a reactive storage Unit that is loosely based on `Map`.
 *
 * It only accepts plain dictionary `object` as its value.
 * It ensures that at any point of time the value would always be a dictionary `object`.
 *
 * Learn more about Units [here](https://docs.activejs.dev/fundamentals/units). \
 * Learn more about DictUnit [here](https://docs.activejs.dev/fundamentals/units/dictunit).
 *
 * Just like every other Non-Primitive ActiveJS Unit:
 * - DictUnit extends {@link NonPrimitiveUnitBase}
 * - Which further extends {@link UnitBase}, {@link Base} and `Observable`
 *
 * @category 1. Units
 */
export declare class DictUnit<T extends DictValue<T>, K extends keyof T = keyof T, V extends T[K] = T[K]> extends NonPrimitiveUnitBase<T> {
    /**
     * @internal please do not use.
     */
    protected readonly eventsSubject: Subject<DictUnitEvents<T>>;
    /**
     * On-demand observable events.
     */
    readonly events$: Observable<DictUnitEvents<T>>;
    /**
     * The length of keys of the properties in the dictionary {@link value}.
     */
    get length(): number;
    /**
     * Indicates whether the length of the keys of the properties in the dictionary {@link value} is 0 or not.
     */
    get isEmpty(): boolean;
    /**
     * @internal please do not use.
     */
    protected defaultValue(): T;
    constructor(config?: UnitConfig<T>);
    /**
     * Extends {@link UnitBase.wouldDispatch} and adds additional check for Object dictionary {@link isDict},
     * which cannot be bypassed even by using {@link force}.
     *
     * @param value The value to be dispatched.
     * @param force Whether dispatch-checks should be bypassed or not.
     * @returns A boolean indicating whether the param `value` would pass the dispatch-checks if dispatched.
     *
     * @category Common Units
     */
    wouldDispatch(value: T, force?: boolean): boolean;
    /**
     * Adds a property by setting given property-value on the given key in the dictionary {@link value}. \
     * Also, dispatches it as new dictionary, without mutating the current {@link value}.
     *
     * It only works if the Unit is not frozen and the `key` is either `string` or `number`.
     *
     * @param key The name of the property.
     * @param value The property-value.
     *
     * @triggers {@link EventDictUnitSet}
     * @category Custom DictUnit
     */
    set<k extends K>(key: k, value: T[k]): void;
    /**
     * Deletes properties with given keys from the dictionary value. See {@link value}. \
     * Deletion is performed on a copy of the value, which is then dispatched, without mutating the current value.
     *
     * It only works if the Unit is not frozen, and the value is not empty, \
     * and at least one of the passed keys exist in the value.
     * ie: at least 1 key value pair exists in the dictionary.
     *
     * @param keys The names of the properties to be removed.
     * @returns The removed properties or an empty `object-literal`.
     *
     * @triggers {@link EventDictUnitDelete}
     * @category Custom DictUnit
     */
    delete<k extends K>(...keys: k[]): {
        [key in k]: T[k];
    };
    /**
     * Deletes properties from the dictionary {@link value} where the predicate returns `true`. \
     * Also, dispatches it as new dictionary, without mutating the current {@link value}.
     *
     * It only works if the Unit is not frozen, and
     * the predicate is a function, and the dictionary is not empty.
     *
     * @param predicate A callback function that gets called for every property in the dictionary
     * with the property-value and key as arguments.
     * @returns The removed properties, or an empty `object-literal`.
     *
     * @triggers {@link EventDictUnitDelete}
     * @category Custom DictUnit
     */
    deleteIf(predicate: (value: V, key: K, index: number) => boolean): T;
    /**
     * Copy the values of all the enumerable own properties from one or more source objects to the dictionary. \
     * Also, dispatches it as new dictionary, without mutating the current {@link value}.
     *
     * It only works if the Unit is not frozen, and at least 1 source is provided, and it is a non-null object.
     * eg: `array`, `object`
     *
     * @param sources The source objects from which to copy properties.
     *
     * @triggers {@link EventDictUnitAssign}
     * @category Custom DictUnit
     */
    assign(...sources: T[]): void;
    /**
     * Returns the value of the property with the name equal to the given key in the dictionary {@link value}.
     *
     * It only returns own-properties, e.g.: key 'toString' would return `undefined`.
     *
     * @param key The name of the property.
     *
     * @category Custom DictUnit
     */
    get<k extends K>(key: k): T[k] | undefined;
    /**
     * Returns whether a property with the given key exists in the dictionary {@link value}.
     *
     * @param key The name of the property.
     *
     * @category Custom DictUnit
     */
    has<k extends K>(key: k): boolean;
    /**
     * Finds direct properties of the dictionary that have a direct child property
     * that matches with `key` and `value` passed as params.
     *
     * @example
     * ```ts
     * const initialValue = {'first': {b: 1}, 'second': {b: 1, b2: 2}, 'third': {c: 1}, 'fourth': {b: null}};
     * const dict = new DictUnit({initialValue});
     * const itemsFound = dict.findByProp('b', 1);
     * console.log(itemsFound); // logs [['first', {b: 1}], ['second', {b: 1, b2: 2}]]
     * ```
     *
     * @param key The key of the property whose value needs to be matched against param `value`.
     * @param value A primitive value that will be matched against every item's prop-value using equality operator.
     * @param strictEquality A flag governing whether the value be matched using `===` or `==` operator.
     * Default is `true`, ie: strict equality `===`. Pass `false` to use `==` instead.
     * @returns An `array` of key/values of the matched properties, an empty `array` otherwise.
     *
     * @category Custom DictUnit
     */
    findByProp<k extends KOf<V>>(key: k, value: string | number | boolean, strictEquality?: boolean): [K, V][];
    /**
     * Performs the specified action for each property in the object value. See {@link value}. \
     * It's a drop-in replacement for the `forEach` method.
     *
     * @param callbackFn A function that accepts up to two arguments.
     * forEvery calls the callbackFn function one time for each property in the object value.
     * @param thisArg An object to which this keyword can refer in the callbackFn function.
     * If thisArg is omitted, undefined is used as this value.
     *
     * @category Custom DictUnit
     */
    forEvery(callbackFn: (value: V, key: K, index: number, entries: [K, V][]) => void, thisArg?: any): void;
    /** Iterator */
    [Symbol.iterator](): Iterator<[string, V]>;
    /**
     * @internal please do not use.
     */
    protected isValidValue(value: any): boolean;
}