type StringifyReplacer = (this: any, key: string, value: any) => any;
/**
 * A stable stringify function that sorts object keys before stringifying
 * so that identical objects with different key ordering will stringify to identical
 * strings.
 *
 * If the object being stringified contains cycles, the deeper appearance
 * of the cycled object will be replaced with the string '__cycle__'
 */
export declare function stringify(data: any, replacer?: StringifyReplacer): string;
/**
 * Frequently you just want to make sure you have a string in order
 * to key an object, but it's not technically for JSON purposes and
 * you don't want to add quotes around an existing string.
 *
 * stringify('mystring') === '"mystring"'
 * ensureString('mystring') === 'mystring'
 */
export declare function ensureString(data: undefined): undefined;
export declare function ensureString(data: any): string;
export {};