/**
 * Pure helper: compute the desired `html.customData` array for a project.
 *
 * Returns `null` when no change is required (the existing array already matches),
 * otherwise the new array that should be written.
 *
 * The produced entry is a project-relative path with forward slashes. We use
 * `path.relative` rather than a string replace because Vite normalises projectRoot
 * to forward slashes while `htmlDataPath` carries the platform separator from
 * `path.join` — a naive replace fails to match on Windows and leaves an absolute path.
 * Any pre-existing entry pointing at a `needle-html-data.json` (e.g. an absolute path
 * written by an older version of this plugin) is dropped so we don't accumulate
 * duplicates or leave stale absolute paths behind.
 *
 * Exported for testing. The `relativeFn` seam lets tests reproduce platform-specific
 * separator behaviour (`path.win32.relative` / `path.posix.relative`) deterministically.
 *
 * @param {unknown[]} existing  Current html.customData entries
 * @param {string} projectRoot
 * @param {string} htmlDataPath  Absolute path to the generated needle-html-data.json
 * @param {(from: string, to: string) => string} [relativeFn]
 * @returns {string[] | null}
 */
export function computeHtmlCustomData(existing: unknown[], projectRoot: string, htmlDataPath: string, relativeFn?: (from: string, to: string) => string): string[] | null;
/**
 * @param {"build" | "serve"} _command  Vite command (unused — runs in both modes)
 * @param {import('../types/needleConfig').needleMeta | null | undefined} _config
 * @param {import('../types').userSettings} [_userSettings]
 * @returns {import('vite').Plugin | null}
 */
export function needleDtsGenerator(_command: "build" | "serve", _config: import("../types/needleConfig").needleMeta | null | undefined, _userSettings?: import("../types").userSettings): import("vite").Plugin | null;