export type HelpfulErrorMetadata = Record<string, any> & {
    cause?: Error;
};
/**
 * HelpfulError errors are used to add information that helps the future observer of the error understand whats going on
 */
export declare class HelpfulError extends Error {
    constructor(message: string, metadata?: HelpfulErrorMetadata);
    /**
     * a utility to throw an error of this class, for convenience
     *
     * e.g.,
     * ```ts
     * const phone = customer.phone ?? HelpfulError.throw('expected a phone');
     * ```
     */
    static throw<T extends typeof HelpfulError>(this: T, // https://stackoverflow.com/a/51749145/3068233
    message: string, metadata?: HelpfulErrorMetadata): never;
    /**
     * an override to ensure that errors are serialized to json expressively
     *
     * ref
     * - https://stackoverflow.com/a/18391400/3068233
     * - https://github.com/nodejs/node/issues/29090
     */
    toJSON<T extends typeof HelpfulError>(this: T, // https://stackoverflow.com/a/51749145/3068233
    message: string, metadata?: HelpfulErrorMetadata): Record<string, any>;
}