/** Asserts that the given predicate is true, otherwise throws an error. */
export declare function assert(predicate: boolean, message: string): asserts predicate;
/** Asserts that the given object has the given field using `Object.hasOwn`. */
export declare function assertHasOwn<K extends PropertyKey>(x: object, k: K): asserts x is Record<K, unknown>;
/** Asserts that the given object is an instance of the given class. */
export declare function assertInstanceOf<T>(x: unknown, cls: new (...args: any[]) => T): asserts x is T;