function extractRequiredInfo(command) {
  const jsTsFileMatcher = new RegExp('^(t|j)s', 'i');
  return {
    fromVersion: command.opts().from,
    toVersion: command.opts().to || 'latest',
    fileNames: command.processedArgs[0].filter((filename) => {
      return jsTsFileMatcher.test(filename.split('.').pop());
    }),
  };
}
Extracts the from-version, to-version, and file names from the options and
arguments.
@param {Command} command The command to extract the info from.
@returns {{
  fromVersion: string,
  toVersion:string,
  fileNames: !Array<string>}} The required info.