export declare function assert(predicate: boolean | (() => boolean), message?: string): asserts predicate;
export declare function notNull(object: any): boolean;
/**
 * Ensures that obj2 contains all keys from obj1.
 * @param obj1
 * @param obj2
 * @returns
 */
export declare function deepDirectionalEqual(obj1: any, obj2: any, seenObjects?: WeakSet<object>): boolean;