/**
 * This function is used to mark string literals representing CSS class names
 * so that they can be transformed statically. This allows for modularization
 * and minification of CSS class names.
 *
 * In static_upstream, this function is actually implemented, but it should
 * eventually be replaced with something more descriptive, and the transform
 * that is used in the main stack should be ported for use elsewhere.
 *
 * @param string|object className to modularize, or an object of key/values.
 *                      In the object case, the values are conditions that
 *                      determine if the className keys should be included.
 * @param [string ...]  Variable list of classNames in the string case.
 * @return string       Renderable space-separated CSS className.
 */
declare function cx(classNames: string | string[] | object): string;

declare namespace cx {}

export = cx;