/**
 * @TODO: could trim too
 */
export function isRel(url: string) {
  if (!url || !url.slice) {
    return false
  } else {
    return (
      /^(\.){1,2}(\/){1,2}$/.test(url.slice(0, 3)) ||
      /(\/){1,2}(\.){1,2}(\/){1,2}/.test(url) ||
      url.indexOf('./') === 0 ||
      url.indexOf('../') === 0
    )
  }
}