code: function getFileSize(filePath, callback) {
    try {
      isDirectory(filePath, function (err, data) {
        if (data) {
          callback(null, -1);
        } else {
          fs.stat(filePath, function (err, data) {
            if (err) {
              callback(null, -1);
            } else {
              callback(null, data.size);
            }
          });
        }
      });
    } catch (error) {
      callback(null, -1);
    }
  }
docs: /*
  @function getFileSize (private)
  @description Returns the size of a file
  @param {string} filePath [Path of the file]
  @param callback