MongoDB + Node.js：如何将外部文件中的Schema用于另一个Schema？

I have a classes (or models) that needs to use another class as part of its properties as shown below.

我有一个类(或模型)需要使用另一个类作为其属性的一部分,如下所示。

** Header for both files **

**两个文件的标题**

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

item.js

module.exports = function() {
    var ItemSchema = new Schema({
        name: String,
        cost: Number
    });
    mongoose.model('Item', ItemSchema);
}

receipt.js

ItemModel = require('./item.js');

var Item = mongoose.model('Item');

module.exports = function() {

    var LineItemSchema = new Schema({
        item:   Item,
        amount: Number
    });

    var LineItem = mongoose.model('LineItem', LineItemSchema);

    var ReceiptSchema = new Schema({
        name:   String,
        items:  [LineItemSchema]
    });
    mongoose.model('Receipt', ReceiptSchema);
}

In the LineItem class, I'm trying to set the type of the variable 'item' to the class type, Item, node.js or mongoose.js is screaming at me about it saying that there's a type error.

在LineItem类中,我试图将变量'item'的类型设置为类类型,Item,node.js或mongoose.js正在尖叫着我说它有类型错误。

How can I use a Schema "type" from an external file?

如何使用外部文件中的Schema“type”?

2 个解决方案

#1

I have no idea why you are wrapping all of this in an anonymous function. But to reference a schema from another schema, you can do the following:

我不知道你为什么要在匿名函数中包装所有这些。但是要从另一个模式引用模式,您可以执行以下操作:

var LineItemSchema = new Schema({
    item: {
        type: Schema.ObjectId,
        ref: 'Item'
    },
    amount: Number
});

And of course you need to require the Schema object:

当然,您需要需要Schema对象:

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

#2

In item.js have it return the schema from a self-executing function.

在item.js中,它从自执行函数返回模式。

module.exports = (function() {
    var ItemSchema = new Schema({
        name: String,
        cost: Number
    });
    mongoose.model('Item', ItemSchema);
    return ItemSchema;
})();

Then in receipt.js you now can use the schema just like you used LineItemSchema.

然后在receipt.js中,您现在可以像使用LineItemSchema一样使用模式。

var ItemSchema = require('./item.js');

// This should still create the model just fine.
var Item = mongoose.model('Item');

module.exports = function() {

var LineItemSchema = new Schema({
    item:   [ItemSchema], // This line now can use the exported schema.
    amount: Number
});

var LineItem = mongoose.model('LineItem', LineItemSchema);

var ReceiptSchema = new Schema({
    name:   String,
    items:  [LineItemSchema]
});
mongoose.model('Receipt', ReceiptSchema);

}

This is all speculation and untested.

这是所有猜测和未经测试。

#1