refactor: more readable (#132)

src/listener.ts

@@ -55,12 +55,11 @@ const responseViaResponseObject = async (
  res: Response | Promise<Response>,
  outgoing: ServerResponse | Http2ServerResponse
 ) => {
- if (res instanceof Promise) {
- res = await res.catch(handleFetchError)
- }
+ res = res instanceof Promise ? await res.catch(handleFetchError) : res
 
  try {
- if (cacheKey in res) {
+ const isCached = cacheKey in res
+ if (isCached) {
  return responseViaCache(res as Response, outgoing)
  }
  } catch (e: unknown) {
@@ -79,20 +78,30 @@ const responseViaResponseObject = async (
  * Else if content-type is not application/json nor text/* but can be text/event-stream,
  * we assume that the response should be streamed.
  */
+
+ const {
+ 'transfer-encoding': transferEncoding,
+ 'content-encoding': contentEncoding,
+ 'content-length': contentLength,
+ 'x-accel-buffering': accelBuffering,
+ 'content-type': contentType,
+ } = resHeaderRecord
+
  if (
- resHeaderRecord['transfer-encoding'] ||
- resHeaderRecord['content-encoding'] ||
- resHeaderRecord['content-length'] ||
+ transferEncoding ||
+ contentEncoding ||
+ contentLength ||
  // nginx buffering variant
- (resHeaderRecord['x-accel-buffering'] &&
- regBuffer.test(resHeaderRecord['x-accel-buffering'] as string)) ||
- !regContentType.test(resHeaderRecord['content-type'] as string)
+ (accelBuffering && regBuffer.test(accelBuffering as string)) ||
+ !regContentType.test(contentType as string)
  ) {
  outgoing.writeHead(res.status, resHeaderRecord)
+
  await writeFromReadableStream(res.body, outgoing)
  } else {
  const buffer = await res.arrayBuffer()
  resHeaderRecord['content-length'] = buffer.byteLength
+
  outgoing.writeHead(res.status, resHeaderRecord)
  outgoing.end(new Uint8Array(buffer))
  }