function supportES2015(tsConfigPath) {
  if (!supportES2015.hasOwnProperty('supportES2015')) {
    const tsTarget = readTsConfig(tsConfigPath).options.target;
    supportES2015['supportES2015'] = tsTarget !== ts.ScriptTarget.ES3 && tsTarget !== ts.ScriptTarget.ES5;
  }
  return supportES2015['supportES2015'];
}
This suffix is added to the environment.ts file, if not set the default environment file is loaded (development)
To disable environment files set this to null