Function dispatchWithProtocolPreference

lib/web/fetch/index.js:2203–2417

(body, allowH2)

    return dispatchWithProtocolPreference(body)

    function dispatchWithProtocolPreference (body, allowH2) {
      return new Promise((resolve, reject) => agent.dispatch(
        {
          path: hasTrailingQuestionMark ? `${path}?` : path,
          origin: url.origin,
          method: request.method,
          body: agent.isMockActive ? request.body && (request.body.source || request.body.stream) : body,
          // Preserve the serialized fetch body for MockAgent net-connect fallthroughs.
          __mockAgentBodyForDispatch: body,
          headers: request.headersList.entries,
          maxRedirections: 0,
          upgrade: request.mode === 'websocket' ? 'websocket' : undefined,
          ...(allowH2 === false ? { allowH2 } : null)
        },
        {
          body: null,
          abort: null,

          onRequestStart (controller) {
            // TODO (fix): Do we need connection here?
            const { connection } = fetchParams.controller

            // Set timingInfo’s final connection timing info to the result of calling clamp and coarsen
            // connection timing info with connection’s timing info, timingInfo’s post-redirect start
            // time, and fetchParams’s cross-origin isolated capability.
            // TODO: implement connection timing
            timingInfo.finalConnectionTimingInfo = clampAndCoarsenConnectionTimingInfo(undefined, timingInfo.postRedirectStartTime, fetchParams.crossOriginIsolatedCapability)

            const abort = (reason) => controller.abort(reason)

            if (connection.destroyed) {
              abort(new DOMException('The operation was aborted.', 'AbortError'))
            } else {
              fetchParams.controller.on('terminated', abort)
              this.abort = connection.abort = abort
            }

            // Set timingInfo’s final network-request start time to the coarsened shared current time given
            // fetchParams’s cross-origin isolated capability.
            timingInfo.finalNetworkRequestStartTime = coarsenedSharedCurrentTime(fetchParams.crossOriginIsolatedCapability)
          },

          onResponseStarted () {
            // Set timingInfo’s final network-response start time to the coarsened shared current
            // time given fetchParams’s cross-origin isolated capability, immediately after the
            // user agent’s HTTP parser receives the first byte of the response (e.g., frame header
            // bytes for HTTP/2 or response status line for HTTP/1.x).
            timingInfo.finalNetworkResponseStartTime = coarsenedSharedCurrentTime(fetchParams.crossOriginIsolatedCapability)
          },

          onResponseStart (controller, status, headers, statusText) {
            if (status < 200) {
              return
            }

            const rawHeaders = controller?.rawHeaders ?? []
            const headersList = new HeadersList()
            appendHeadersListFromResponseHeaders(headersList, headers, rawHeaders)