javascript function never returns true, do you know why?

I wanna test if a field exist within a map function. If the field exist, it should assign a value to a variable, if not, it should assign an empty string to it. It never change the condition to true even if an object exist (msg variable is always empty). Do you know why?

Object.keys(editorJSON).map((key) => {
if (editorJSON[key].name === "Frage") {
    const message = () => {
      if (typeof editorJSON[key + 1] !== "undefined") {
        const msg = editorJSON[key + 
        1].data.chatbottext;
        return msg;
      } else {
        const msg = "testantwort";
        return msg;
      }
    };

}

Thank you very much, very appreciate your help