/**
 * Concatenates the list of classes given into a single class string.
 *
 * If a parameter is `false` or `undefined`, then it will be ignored. This
 * is useful for building a single class string out of several classes,
 * some of which are conditionally included.
 *
 * @example
 * // When isActive is true, returns "link active"
 * // When isActive is false, returns "link inactive"
 * concatClasses(
 *     "link",
 *     isActive && "active",
 *     !isActive && "inactive"
 * )
 *
 * @example
 * // Ehen props.icon is defined, returns "base with-icon"
 * // When props.icon is undefined, returns "base"
 * concatClasses(
 *     "base",
 *     props.icon && "with-icon"
 * )
 */
export declare function concatClasses(...classes: (string | false | undefined)[]): string;