Node.js 嵌入式文档的Mongoose更新

我在尝试理解如何在mongoose中更新嵌入文档的值时，慢慢变得疯狂，并编写了一些node.js代码来演示这个问题

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

mongoose.connect('mongodb://localhost/mongoose_broken');

var ASchema = new Schema({
   value : { type: String, index: { unique: true } },
   bs    : [BSchema],
});
var BSchema = new Schema({
   value : { type: String },
});
var A = mongoose.model('A', ASchema);
var B = mongoose.model('B', BSchema);

// Add an entry of A, with 1 embedded B
//
var a = new A();
a.value = "hello";
var b = new B();
b.value = "world";
a.bs.push(b);

a.save(function(err) {
   if (err) {
      console.log("Error occured during first save() " + err);
      return;
   }

   // Now update a by changing a value inside the embedded b
   //
   A.findOne({ value: 'hello' }, function(err, doc) {
      if (err) { console.log("Error occured during find() " + err); return; }

      doc.bs[0].value = "moon";

      doc.save(function(err) {
         if (err) console.log("Error occuring during second save()");

         // Check b was updated?
         //
         if (doc.bs[0].value != "moon") {
            console.log ("b was not updated! (first check)");   
         } else {
            console.log ("b looks like it was updated (first check)");

            // Do a fresh find
            //
            A.findOne({value: "hello"}, function(err, doc_2) {
               if (err) { console.log("Error occured during second find() " + err); return; }

               if (doc_2.bs[0].value != "moon") {
                  console.log ("b was not updated! (second check)");   
               } else {
                  console.log ("b looks like it was updated (second check)");
               }
            });
         }
      });
   });
});

运行此命令的输出为：

b looks like it was updated (first check)
b was not updated! (second check)

---

知道为什么不保存嵌入文档的更新吗？

在父模式中使用子模式之前，必须先声明子模式

var BSchema = new Schema({
  value : { type: String },
});    
var ASchema = new Schema({
  value : { type: String, index: { unique: true } },
  bs    : [BSchema],
});

---

如果您执行

console.log（doc_2.bs）doc_2console.log（doc_2.bs）打印“[[Object Object]]”，console.log（doc_2.bs[0]）给出“{value:'world'，_id:4f8ee35f82228240f4300002}”，你知道了-这就解决了它。我认为这是一个bug，因为如果你引用了一个不存在的模式，你会得到一个错误，但当它们出现故障时就不会了。。。真出乎意料！不管怎样，我今晚可以睡个好觉，知道这已经解决了-谢谢亚伦：）这是一个叫做“提升”的东西