/**
 * Escape characters with special meaning either inside or outside character sets.
 *
 * Use a simple backslash escape when it’s always valid, and a `\xnn` escape when the simpler form would be disallowed by Unicode patterns’ stricter grammar.
 *
 * Taken from https://github.com/sindresorhus/escape-string-regexp/
 */
export declare function escapeStringRegexp(string: string): string;