Function buildDevStylesUrl

packages/router-core/src/utils.ts:690–699

(
  basepath: string,
  routeIds: Array<string>,
)

 * @returns The full URL path for the dev styles CSS endpoint
 */
export function buildDevStylesUrl(
  basepath: string,
  routeIds: Array<string>,
): string {
  // Trim all leading and trailing slashes from basepath
  const trimmedBasepath = basepath.replace(/^\/+|\/+$/g, '')
  // Build normalized basepath: empty string for root, or '/path' for non-root
  const normalizedBasepath = trimmedBasepath === '' ? '' : `/${trimmedBasepath}`
  return `${normalizedBasepath}/@tanstack-start/styles.css?routes=${encodeURIComponent(routeIds.join(','))}`
}