import { Iterator } from "../../lazy";
import { Options } from "../../types";
import { TimeUnit } from "../expression/date/_internal";
interface InputExpr {
    /**
     * The field to densify. The values of the specified field must either be all numeric values or all dates.
     * AnyObjects that do not contain the specified field continue through the pipeline unmodified.
     * To specify a <field> in an embedded document or in an array, use dot notation.
     */
    field: string;
    range: {
        step: number;
        bounds: "full" | "partition" | [number, number] | [Date, Date];
        unit?: TimeUnit;
    };
    partitionByFields?: string[];
}
/**
 * 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}.
 */
export declare function $densify(coll: Iterator, expr: InputExpr, options: Options): Iterator;
export {};