/**
* Opt-in response decompression. Most runtimes (Node 22+, Bun, Deno) auto-
* decompress gzip/br responses at the fetch layer; this module exists for
* formats they don't (zstd, until widely shipped) and for custom drivers
* that don't decompress at all.
*/
export type DecompressFormat = "gzip" | "deflate" | "deflate-raw" | "br" | "zstd";
/**
* Capability-test which formats the runtime's `DecompressionStream`
* actually supports. Returns the intersection of the user's request and
* runtime support.
*/
export declare function detectSupportedFormats(requested: readonly DecompressFormat[] | true): DecompressFormat[];
/**
* Wrap a Response in a DecompressionStream when its `Content-Encoding`
* matches one of the formats AND the body hasn't already been decoded.
*
* Heuristic for "already decoded": if the runtime delivered a decoded
* response, `Content-Length` typically no longer matches the encoded size
* and `Content-Encoding` may be stripped. We act conservatively — only
* decompress when `Content-Encoding` is still present.
*/
export declare function maybeDecompress(response: Response, formats: readonly DecompressFormat[]): Response;
/**
* Build the `Accept-Encoding` header value from a runtime-supported list.
* Returns undefined if the list is empty (don't advertise nothing).
*/
export declare function acceptEncodingFor(formats: readonly DecompressFormat[]): string | undefined;