/** Assertion functions for runtime and type safety. */
/**
 * Assert that a value is defined.
 *
 * @example Const stringify = (value: number | undefined): number => {
 * assertExists(value) return `${value}` // TS now knows that value is of type
 * `number` }
 */
export declare const assertExists: <T>(value: T, message: string) => asserts value is NonNullable<T>;