/**
 * Flatten options.
 */
export type Options = {
    /**
     * If true, arrays will be flattened and their indexes will be used as keys.
     * @default false
     * @example
     * ```ts
     * flatten({ rules: [{value: 7}] }, { array: true });
     * // { $set: { 'rules.0.value': 7 } }
     *
     * flatten({ rules: [{value: 7}] }, { array: false });
     * // { $set: { 'rules': [{value: 7}] } }
     * ```
     */
    array?: boolean;
    /**
     * If true, empty objects are ignored and removed from the flattened result.
     * @default false
     * @example
     * ```ts
     * flatten({ left: {x: 1}, right: {} }, { skipEmptyObjects: true });
     * // { $set: { 'left.x': 1 } }
     *
     * flatten({ left: {x: 1}, right: {} }, { skipEmptyObjects: false });
     * // { $set: { 'left.x': 1, 'right': {} } }
     * ```
     */
    skipEmptyObjects?: boolean;
};
/**
 * Transforms a given object into the MongoDB's update instructions.
 * @param value the input object to transform
 *
 * @example
 * ```ts
 * flatten({
 *   first_name: $rename('firstName'),
 *   lastName: 'Doe',
 *   updatedOn: $timestamp(),
 *   address: {
 *     primary: true
 *   },
 *   access: $push(new Date()),
 * });
 *
 * // equivalent to:
 * {
 *   "$rename": {
 *     "first_name": "firstName"
 *   },
 *   "$set": {
 *     "lastName": "Doe",
 *     "address.primary": true
 *   },
 *   "$currentDate": {
 *     "updatedOn": {
 *       "$type": "timestamp"
 *     }
 *   },
 *   "$push": {
 *     "access": new Date()
 *   }
 * }
 * ```
 *
 * @example
 * ```ts
 * // update arrays
 * flatten({ scores: [{ value: 4 }, {value: 2}] }, { array: true} );
 *
 * // equivalent to:
 * {
 *   "$set": {
 *     "scores.0.value": 4,
 *     "scores.1.value": 2,
 *   }
 * }
 * ```
 */
export declare const flatten: <T extends Record<string, any>>(value: T, options?: Options) => {};