interface ReplicateProps<SourceDocType> {
    /**
     * A function to count the total number of documents
     * in the destination database. This must return a number.
     * @returns A promise that resolves to a number.
     */
    countDestinationDbFn: () => Promise<number>;
    /**
     * A function to count the total number of documents
     * in the source database. This must return a number.
     * @returns A promise that resolves to a number.
     */
    countSourceDbFn: () => Promise<number>;
    /**
     * A function that deletes documents in the destination database,
     * from an array of unique document IDs. This is used to remove any extra documents
     * that are present in the destination database but not in the source database.
     * This function should return a promise that resolves when the deletion is complete.
     * @param uniqueIds An array of unique document IDs to be deleted from the destination database.
     * @returns A promise that resolves when the deletion is complete.
     */
    deleteDestinationDbFn: (uniqueIds: string[]) => Promise<void>;
    /**
     * A function to get the distinct document IDs from the destination database.
     * This must return an array of strings.
     * @returns A promise that resolves to an array of strings.
     */
    distinctDestinationDbFn: () => Promise<string[]>;
    /**
     * A function to get the distinct document IDs from the source database.
     * This must return an array of strings.
     * @returns A promise that resolves to an array of strings.
     */
    distinctSourceDbFn: () => Promise<string[]>;
    /**
     * This is the function that should query the source database for the missing documents based on their IDs.
     * It should return an async iterable (e.g., an async generator or a MongoDB `.stream()`) that yields
     * the missing documents one by one.
     * @param missingDocumentIds An array of document IDs that are missing in the destination database.
     * @returns An async iterable that yields source documents one by one.
     */
    missingDocumentsSourceDbAsyncIterator: (missingDocumentIds: string[]) => AsyncIterable<SourceDocType>;
    /**
     * An optional callback function that will be executed after the replication process is complete.
     * This can be used to perform any necessary cleanup tasks, such as flushing writers or logging.
     */
    onCompleteCallbackFn?: () => Promise<void>;
    /**
     * This function receives a document from the source database and should write it to the destination database.
     * You can use any method you prefer to write the document to the destination database, such as a bulk insert or individual writes,
     * and perform any necessary transformations on the document before writing it.
     * @param sourceDocument The source document to be written to the destination database.
     * @returns A promise that resolves when the document has been successfully written to the destination database.
     */
    writeSourceDocumentToDestinationDbFn: (sourceDocument: SourceDocType) => Promise<void>;
}
/**
 * Copy documents from a source database to a destination database in multiple steps.
 * The goal of this function is to ensure that the destination database has the same documents
 * as the source database. The replication process is designed to be efficient and to minimize
 * the amount of data transferred between the two databases by only syncing the missing documents.
 *
 * 1. First count the total number of documents in both databases to check if they match. This is a
 * crucial optimization step, as it allows us to skip the replication process if both databases already
 * have the same number of documents, which would indicate that they are already in sync.
 * Though, it's important to note that having the same document count does not guarantee
 * that the documents are identical, but it is a quick check to potentially avoid unnecessary replication.
 *
 * 2. If the counts do not match, get the distinct document IDs from both databases and compare them
 * to find out which ones are missing in the destination database. This step is essential to identify
 * the specific documents that need to be replicated, rather than syncing all documents again.
 * Sync only the missing documents from the source database to the destination database,
 *
 * 3. Delete any extra documents in the destination database that are not present in the source database.
 *
 * 4. Run the onComplete callback function if provided. This allows for any additional actions to be performed after
 * the replication process is complete, such as logging, flushing writers or any other necessary cleanup tasks.
 */
export declare function replicate<SourceDocType>({ countDestinationDbFn, countSourceDbFn, deleteDestinationDbFn, distinctDestinationDbFn, distinctSourceDbFn, missingDocumentsSourceDbAsyncIterator, onCompleteCallbackFn, writeSourceDocumentToDestinationDbFn }: ReplicateProps<SourceDocType>): Promise<void>;
export {};