function acquireKernelInfo()

in src/Explorer/Notebook/NotebookComponent/epics.ts [136:214]
72 lines of code
6 McCabe index (conditional complexity)

function acquireKernelInfo(channels: Channels, kernelRef: KernelRef, contentRef: ContentRef) {
  const message = createMessage("kernel_info_request");

  const obs = channels.pipe(
    childOf(message),
    ofMessageType("kernel_info_reply"),
    first(),
    mergeMap((msg) => {
      const content = msg.content;
      const languageInfo = (content && content.language_info) || {
        name: "",
        version: "",
        mimetype: "",
        file_extension: "",
        pygments_lexer: "",
        codemirror_mode: "",
        nbconvert_exporter: "",
      };

      switch (languageInfo.name) {
        case "csharp":
          languageInfo.codemirror_mode = "text/x-csharp";
          break;
        case "scala":
          languageInfo.codemirror_mode = "text/x-scala";
          break;
      }

      const info: KernelInfo = {
        protocolVersion: content.protocol_version,
        implementation: content.implementation,
        implementationVersion: content.implementation_version,
        banner: content.banner,
        helpLinks: content.help_links,
        languageName: languageInfo.name,
        languageVersion: languageInfo.version,
        mimetype: languageInfo.mimetype,
        fileExtension: languageInfo.file_extension,
        pygmentsLexer: languageInfo.pygments_lexer,
        codemirrorMode: languageInfo.codemirror_mode,
        nbconvertExporter: languageInfo.nbconvert_exporter,
      };

      let result;
      if (!content.protocol_version.startsWith("5")) {
        result = [
          actions.launchKernelFailed({
            kernelRef,
            contentRef,
            error: new Error(
              "The kernel that you are attempting to launch does not support the latest version (v5) of the messaging protocol.",
            ),
          }),
        ];
      } else {
        result = [
          // The original action we were using
          actions.setLanguageInfo({
            langInfo: msg.content.language_info,
            kernelRef,
            contentRef,
          }),
          actions.setKernelInfo({
            kernelRef,
            info,
          }),
        ];
      }

      return of(...result);
    }),
  );

  return Observable.create((observer: Observer<any>) => {
    const subscription = obs.subscribe(observer);
    channels.next(message);
    return subscription;
  });
}