addFileList (fileList) {
    for (let i = 0; i < fileList.length; i++) {
      const file = fileList[i]
      const uuid = token()
      const removeFile = function () {
        this.removeFile(uuid)
      }
      this.files.push({
        progress: false,
        error: false,
        complete: false,
        justFinished: false,
        name: file.name || 'file-upload',
        file,
        uuid,
        path: false,
        removeFile: removeFile.bind(this),
        previewData: file.previewData || false
      })
    }
  }
Produce an array of files and alert the callback.
@param {FileList}