code: function (file) {
          var self = this,
              ext = path.extname(file.name).toLowerCase();
          return this.isZip(ext) ? self.processZip(file) : self.processFile(file, ext);
      }
docs: Import Step 1:
  Load the given file into usable importData in the format: {data: {}, images: []}, regardless of
  whether the file is a single importable file like a JSON file, or a zip file containing loads of files.
  @param {File} file
  @returns {Promise}