I have a binaries storage bucket (in Firebase Storage) and I am implementing a node.js Cloud Function which gets an audio (audio/m4a or audio/caf), verifies it format and duration, and then associate its uri with a document in my database (or deletes the audio file if its duration is not valid).

Before creating the document in my database, I need to validate the audio file.

For downloading the files from the storage I am using this function:

exports.downloadBinaryFileFromUrl = function (fileUrl) {
  /* This function downloads a binary-encoded file from its URL and returns it */
  return axios
    .get(fileUrl, {
      responseType: "arraybuffer",
    })
    .then((res) => Buffer.from(res.data, "binary"))
    .catch((err) => {
      if (err.response) {
        /* 
          The request was made and the server responded with a status code
          that falls out of the range of 2xx
        */
        throw err.response.data;
      } else if (err.request) {
        // Client never received a response, or request never left
        throw err.request;
      } else {
        // Something happened in setting up the request that triggered an Error
        throw new Error(`Error: ${err.message}`);
      }
    });
};

Any ideas how to get the audio file's duration using Node.js?