export interface UniFlattenOptions {
    circularReference?: 'string' | 'symbol' | 'null';
    strict?: boolean;
    /**
     * Whether to unflatten class instances.
     * When enabled, a special symbol will be added to the flattened object.
     * When unflattening, the symbol will be used to identify class instances.
     * Default is false.
     */
    unflattenToClassInstances?: boolean;
    /**
     * Whether to flatten class instances.
     * Properties on the prototype chain will not be flattened.
     * Default is false.
     */
    flattenClassInstances?: boolean;
    /**
     * Defines a custom serializer when flattening the object.
     * This may break `unflatten` function (depending on your serializer)
     * @param key current key to serialize
     * @param prefix previously serialized keys
     * @param meta information about current key
     */
    serializeFlattenKey?: (key: string, prefix: string, meta: {
        /** returns true when the key is array index */
        isArrayIndex: boolean;
        /** returns true when the key contains special characters which can not be used in javascript variables */
        hasSpecialCharacters: boolean;
        /** returns true when the key can be used in dot notation */
        canUseDotNotation: boolean;
    }) => string;
}