/**
 * Handle models (i.e. docs)
 * Serialization/deserialization
 * Copying
 * Querying, update
 */
/**
 * Check a key, throw an error if the key is non valid
 * @param {String} key key
 * @param {Model} value value, needed to treat the Date edge case
 * Non-treatable edge cases here: if part of the object if of the form { $$date: number } or { $$deleted: true }
 * Its serialized-then-deserialized version it will transformed into a Date object
 * But you really need to want it to trigger such behaviour, even when warned not to use '$' at the beginning of the field names...
 */
export declare function checkKey(key: number | string, value: any): void;
/**
 * Check a DB object and throw an error if it's not valid
 * Works by applying the above checkKey function to all fields recursively
 */
export declare function checkObject(obj: Record<string, any>[] | Record<string, any>): void;
/**
 * Deep copy a DB object
 * The optional strictKeys flag (defaulting to false) indicates whether to copy everything or only fields
 * where the keys are valid, i.e. don't begin with $ and don't contain a .
 */
export declare function deepCopy<T>(obj: T & {
    _id?: string;
}, strictKeys?: boolean): T;
/**
 * Tells if an object is a primitive type or a "real" object
 * Arrays are considered primitive
 */
export declare function isPrimitiveType(obj: any): boolean;
/**
 * Compare { things U undefined }
 * Things are defined as any native types (string, number, boolean, null, date) and objects
 * We need to compare with undefined as it will be used in indexes
 * In the case of objects and arrays, we deep-compare
 * If two objects dont have the same type, the (arbitrary) type hierarchy is: undefined, null, number, strings, boolean, dates, arrays, objects
 * Return -1 if a < b, 1 if a > b and 0 if a = b (note that equality here is NOT the same as defined in areThingsEqual!)
 *
 * @param a
 * @param b
 * @param {Function} _compareStrings String comparing function, returning -1, 0 or 1, overriding default string comparison (useful for languages with accented letters)
 */
export declare function compareThings(a: any, b: any, _compareStrings?: (a: string, b: string) => number): any;
/**
 * Modify a DB object according to an update query
 */
export declare function modify(obj: any, updateQuery: any): any;
/**
 * Get a value from object with dot notation
 * @param {Object} obj
 * @param {String} field
 */
export declare function getDotValue(obj: any, field: any): any;
/**
 * Check whether 'things' are equal
 * Things are defined as any native types (string, number, boolean, null, date) and objects
 * In the case of object, we check deep equality
 * Returns true if they are, false otherwise
 */
export declare function areThingsEqual(a: any, b: any): boolean;
/**
 * Check that two values are comparable
 */
export declare function areComparable(a: any, b: any): boolean;
/**
 * Tell if a given document matches a query
 * @param {Object} obj Document to check
 * @param {Object} query
 */
export declare function match(obj: any, query: any): boolean;