export declare class ObjectHelper {
    static isDefined(value: any): boolean;
    static isObject(value: any): boolean;
    /**
     * Check if the object is a string or array before evaluating the length attribute.
     * This avoids falsely rejecting objects that contain a custom length attribute.
     * For example, the object {id: 1, length: 0, width: 0} should not be returned as empty.
     */
    static isEmptyValue(value: any): boolean;
    static isEmpty(obj: any): boolean;
    /**
     * @deprecated The method should not be used. please use deleteNullFields
     */
    static deleteNullKeys(val: any): void;
    static deleteNullFields<T extends {}>(val: T): T | undefined;
    static assignFields<T extends {}, U extends {}>(target: T, source: U): T;
    static deepCopy<T = any>(value: any): T;
    static deepEquals(a: any, b: any): boolean;
}