import { PipelineOperator } from "../../core";
/**
 * Creates new documents in a sequence of documents where certain values in a field are missing.
 *
 * {@link https://www.mongodb.com/docs/manual/reference/operator/aggregation/densify usage}.
 *
 * @param collection
 * @param expr
 * @param options
 * @returns
 */
export declare const $densify: PipelineOperator;