Question

我正在尝试创建一个原型方法来获取对象中的嵌套属性（如果不存在则返回null）。

Object.prototype.getNested = function() {
  var args = Array.prototype.slice.call(arguments);
  var obj = this;
  for (var i = 0; i < args.length; i++) {
    if (!obj.hasOwnProperty(args[i])) return null;
    obj = obj[args[i]];
  }
  return obj;
};

所以我收到了这个错误：

uncaughtException: Cowardly refusing to pack object with circular reference getNested

这个错误意味着什么？我以前从未见过这个。

Answer 1

好的，我的猜测是这个错误消息来自msgpack npm module as indicated in the source code here。这意味着您正在尝试序列化引用自身的对象。这是我在节点REPL中重现这个错误：

> var msgpack = require("msgpack");    
> var obj = {};
> obj["me"] = obj;
{ me: [Circular] }
> msgpack.pack(obj);
TypeError: Cowardly refusing to pack object with circular reference
    at Object.pack (/Users/plyons/projects/stackoverflow/node_modules/msgpack/lib/msgpack.js:30:18)
    at repl:1:9
    at REPLServer.self.eval (repl.js:110:21)
    at repl.js:249:20
    at REPLServer.self.eval (repl.js:122:7)
    at Interface.<anonymous> (repl.js:239:12)
    at Interface.emit (events.js:95:17)
    at Interface._onLine (readline.js:202:10)
    at Interface._line (readline.js:531:8)
    at Interface._ttyWrite (readline.js:760:14)

您需要调试该堆栈并查看哪个确切的对象传递给msgpack.pack，然后您就可以了解真正的根本原因。可能只是将getNested添加为属性时，请务必将其标记为不可枚举。

奇怪的错误：懦弱地拒绝用圆形参考包装物体

1 个答案: