code: function loadSequence(index, files) {
        return (
          Promise.resolve()
            // load the file
            .then(function() {
              return new Promise(function(resolve, reject) {
                let myReader = new FileReader();
                // should handle errors too...
                myReader.addEventListener('load', function(e) {
                  resolve(e.target.result);
                });
                myReader.readAsArrayBuffer(files[index]);
              });
            })
            .then(function(buffer) {
              return loader.parse({ url: files[index].name, buffer });
            })
            .then(function(series) {
              seriesContainer.push(series);
            })
            .catch(function(error) {
              window.console.log('oops... something went wrong...');
              window.console.log(error);
            })
        );
      }
docs: Load sequence