使用JavaScript解析JSON

也许有人可以帮我走正确的方向？非常感谢任何提示.

 var credentials = { steam: {}, rpc: {} };
 var rawCredentials = JSON.parse(fs.readFileSync("auth.json", { "encoding": "utf8" }));
 credentials.steam.accountName = rawCredentials.steam.accountName;
 credentials.steam.password = rawCredentials.steam.password;
 credentials.steam.shaSentryfile = new Buffer(rawCredentials.steam.shaSentryfile, "hex");
 credentials.rpc.username = rawCredentials.rpc.username;
 credentials.rpc.password = rawCredentials.rpc.password;

auth.json文件

 {
 "credentials.steam.accountName": "XXX",
 "credentials.steam.password": "XXX",
 }

无法读取未定义的属性"accountName"