@just-in/core/dist/data-manager/data-manager.d.ts

A TypeScript-first framework for building adaptive digital health interventions.

import { EventEmitter } from 'events';
import { CollectionChangeType } from './data-manager.type';
import { DBType } from './data-manager.constants';
import { Readable } from 'stream';
/**
 * Manages database operations and collection change listeners.
 */
declare class DataManager extends EventEmitter {
    protected static instance: DataManager | null;
    private db;
    private changeListenerManager;
    private isInitialized;
    private initializedAt;
    private constructor();
    /**
     * Retrieves the singleton instance of DataManager.
     * @returns {DataManager} The singleton instance.
     */
    static getInstance(): DataManager;
    /**
     * Deletes the singleton instance of DataManager.
     */
    protected static killInstance(): void;
    /**
     * Initializes the DataManager with the specified database type.
     * Sets up listeners for collection changes.
     * @param {DBType} dbType - The type of database to initialize. Defaults to MongoDB.
     * @returns {Promise<void>} Resolves when initialization is complete.
     */
    init(dbType?: DBType): Promise<void>;
    /**
     * Handles `insert` changes in the EVENTS_QUEUE collection.
     * Emits an `eventAdded` signal to notify external systems.
     * @param {any} data - Data from the change stream.
     * @private
     */
    private handleEventsQueueInsert;
    /**
     * Checks if DataManager is initialized.
     * @returns {boolean} Initialization status.
     */
    getInitializationStatus(): boolean;
    /**
     * Closes the DataManager and removes all listeners.
     * @returns {Promise<void>} Resolves when closed.
     */
    close(): Promise<void>;
    checkInitialization(): void;
    /**
     * Adds an item to a specified collection, ensuring the collection exists.
     * Emits a specific event (e.g., `userAdded`) if applicable to the collection.
     * @param {string} collectionName - The name of the collection to which the item will be added.
     * @param {object} item - The item to add to the collection.
     * @returns {Promise<object | null>} Resolves with the added item, or `null` if an error occurs.
     */
    addItemToCollection(collectionName: string, item: object): Promise<object | null>;
    /**
     * Updates an item in a collection by ID and emits an event.
     * @param {string} collectionName - The name of the collection.
     * @param {string} id - The ID of the item to update.
     * @param {object} updateObject - The update data.
     * @returns {Promise<object | null>} Resolves with the updated item or `null` on error.
     */
    updateItemByIdInCollection(collectionName: string, id: string, updateObject: object): Promise<object | null>;
    /**
     * Removes an item from a collection by ID and emits an event.
     * @param {string} collectionName - The name of the collection.
     * @param {string} id - The ID of the item to remove.
     * @returns {Promise<boolean>} Resolves with `true` if removed, `false` on error.
     */
    removeItemFromCollection(collectionName: string, id: string): Promise<boolean>;
    /**
     * Retrieves all items from a collection.
     * @param {string} collectionName - The name of the collection.
     * @returns {Promise<T[] | null>} Resolves with items or `null` on error.
     */
    getAllInCollection<T>(collectionName: string): Promise<T[] | null>;
    /**
     * Clears all items in a collection.
     * @param {string} collectionName - The name of the collection.
     * @returns {Promise<void>} Resolves when the collection is cleared.
     */
    clearCollection(collectionName: string): Promise<void>;
    /**
     * Checks if a collection is empty.
     * @param {string} collectionName - The name of the collection.
     * @returns {Promise<boolean>} Resolves with `true` if empty, `false` on error.
     */
    isCollectionEmpty(collectionName: string): Promise<boolean>;
    /**
     * Finds an item by ID in a specified collection.
     * @template T - The expected type of the item in the collection.
     * @param {string} collectionName - The name of the collection.
     * @param {string} id - The ID of the item to find.
     * @returns {Promise<T | null>} Resolves with the found item of type `T` or `null` if not found or on error.
     */
    findItemByIdInCollection<T>(collectionName: string, id: string): Promise<T | null>;
    /**
   * Finds items by criteria in a specified collection.
   * @template T - The expected type of the item in the collection.
   * @param {string} collectionName - The name of the collection.
   * @param {object} criteria - An object containing the key-value pair to search for. An empty object will return all items.
   *                            If `null`, it will return `null`.
   * @returns {Promise<T[] | null>} Resolves with the found item of type `T` or `null` if not found or on error.
   */
    findItemsInCollection<T>(collectionName: string, criteria: Record<string, any>): Promise<T[] | null>;
    /**
     * Provides a change stream for a specific collection and change type.
     * This method is used by the ChangeListenerManager to abstract away database-specific logic.
     * @param {string} collectionName - The name of the collection to monitor.
     * @param {CollectionChangeType} changeType - The type of change to monitor.
     * @returns {Readable} A readable stream of change events.
     */
    getChangeStream(collectionName: string, changeType: CollectionChangeType): Readable;
}
export default DataManager;
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