Cannot read properties of undefined (reading 'configurations')如此报错，如何解决？(语言-javascript)

**TypeError: Cannot read properties of undefined (reading 'configurations')**如此报错，求助

function dependencyConfig(folder, userConfig) {
  const configurations = userConfig.configurations ||[] ;
  const baseConfig = projectConfig(folder, userConfig);

  if (!baseConfig) {
    return null;
  }

  return { ...baseConfig,
    configurations
  };
}

这报错信息不就是说了读不到文件。
userConfig.configurations ||[] 你后面这个||【】 是什么意思。我不太懂