/**
 * All errors that can occur inside an assert function.
 */
export declare enum OptionsError {
    invalidOptionsParam = 0,
    invalidDefaultsParam = 1,
    optionNotRecognized = 2
}
/**
 * Error-related context available for options-related issues.
 */
export interface IOptionsErrorContext {
    options: any;
    defaults: any;
    key?: string;
}
/**
 * Standard syntax for named values.
 */
export type NamedValues = {
    [name: string]: any;
};
/**
 * Assert function signature.
 */
export type AssertFunc = (options: NamedValues | null | undefined, defaults: NamedValues | string[]) => NamedValues;