为什么这个Node.js插件,Mongoose,不起作用?我遵循了所有指示

TIM*_*MEX 1 mongoose mongodb node.js

mongoose.connect('mongodb://localhost/guesswho');
var Schema = mongoose.Schema;
var Message = new Schema({
    author: { type:String },
    body: { type:String },
});
var MessageModel = mongoose.model("Message");
Run Code Online (Sandbox Code Playgroud)

我按照这里的每条指令:https://github.com/LearnBoost/mongoose

但运行时出现此错误: Error: Schema hasn't been registered for model "Message".

我甚至试过这个:var MessageModel = mongoose.model("Message", Message); 当我这样做时......没有错误.但是,MessageModel未定义.

TIM*_*MEX 5

固定:

var Message = new Schema({
    author: { type:String },
    body: { type:String },
});
mongoose.model("Message",Message);
var MessageModel = mongoose.model("Message");
var aMessage = new MessageModel();
aMessage.author = "apple";
aMessage.body = "orange";
aMessage.save(function(e){

});
Run Code Online (Sandbox Code Playgroud)

来自IRC的人称coreb修复了它.