猫鼬.save()不起作用

我正在运行那些代码，尝试将 保存对象 到 MongoDB 中.

I have those code running try to save an object into MongoDB.

.save()从未成功运行.代码运行良好.

The .save() never got success run. the code running fine.

.save()方法不起作用.

var conn = mongoose.createConnection(mongoUrl, {auth: {authdb: "admin"}});
conn.on('error', function (err) {
    throw err;
});
conn.once('open', function callback() {
    console.log("connected to " + mongoUrl);
    var cacheSchema = mongoose.Schema({}, {strict: false});
    cacheSchema.set('collection', 'caches');
    // you need to specify which connection is uing.
    var Cache = conn.model('cache', cacheSchema);
    var measure = new Cache();
    measure['test'] = "test";
    measure.save(function(err){
        console.log('test');
    });
});