我如何使用 Mongoose.populate - 它不起作用

问题描述

有人可以帮我吗？ 我有两个模式和模型（我添加了完整版的代码来清楚）：

const HouseSchema: Schema = new Schema(
    {
        name: {type: Schema.Types.String,required: true},class: {type: KeydisplayNameSchema},levels: {type: Schema.Types.Number},price: {type: Schema.Types.Number,beginDate: {type: Schema.Types.String},squarePrice: {type: Schema.Types.Number},order: {type: Schema.Types.Number,default: 0},parking: {type: Schema.Types.Boolean},endDate: {type: Schema.Types.String},visibleInCarousel: {type: Schema.Types.Boolean,default: true},isDeleted: {type: Schema.Types.Boolean,default: false},apartmentComplex: {
            type: Schema.Types.ObjectId,ref: 'ApartmentComplex'
        },images: {
            type: imagesSchema,default: () => {
                return {};
            }
        },publishedDate: {type: Schema.Types.String}
    },{
        toJSON: {virtuals: true},toObject: {virtuals: true}
    }
);

HouseSchema.virtual('sections',{
    ref: 'Section',localField: '_id',foreignField: 'house'
});

HouseSchema.virtual('flats',{
    ref: 'Flat',foreignField: 'house'
});

HouseSchema.virtual('layouts',{
    ref: 'HouseLayout',foreignField: 'house'
});

HouseSchema.virtual('levelLayouts',{
    ref: 'LevelLayout',foreignField: 'house'
});

HouseSchema.virtual('parkingComplex',{
    ref: 'ParkingComplex',foreignField: 'houses'
});

const HouseModel = mongoose.model<House>('House',HouseSchema);
export default HouseModel;

const ParkingComplexSchema: Schema = new Schema(
    {
        name: {type: Schema.Types.String,address: {type: Schema.Types.String},city: {type: KeydisplayNameSchema,district: {type: KeydisplayNameSchema,undergroundStation: {type: KeydisplayNameSchema},levels: {type: Schema.Types.Number,beginDate: {type: Schema.Types.String,houses: [
            {
                type: Schema.Types.ObjectId,ref: 'House',default: () => {
                    return [];
                }
            }
        ],developer: {
            type: Schema.Types.ObjectId,ref: 'Developer'
        },ref: 'ApartmentComplex'
        }
    },toObject: {virtuals: true}
    }
);

ParkingComplexSchema.virtual('parkingPlaces',{
    ref: 'ParkingPlace',foreignField: 'parkingComplexId'
});

const ParkingComplexModel = mongoose.model<ParkingComplex>('ParkingComplex',ParkingComplexSchema);

export default ParkingComplexModel;

这些模型相互有参考。

然后我想获得 Parking Complex 并填充字段 'houses'

如果我这样做：

getParkingComplex: async (parent,{uuid}) => {
        const data = await ParkingComplexModel.findById(uuid).exec()
        console.log(data)
        return data;
    }

我得到 Parking Complex 并且字段“houses”有两个 House 的 objectId：

{
  isDeleted: false,houses: [ 60aaa827ec89de07e0fb8db1,60aaa827ec89de07e0fb8db2 ],_id: 60aaa827ec89de07e0fb8db3,levels: 2,beginDate: '2021-09-23T19:07:45.190Z',endDate: '2023-05-23T19:07:45.194Z',developer: 5ecd1c2590de761738c029a3,apartmentComplex: 5ecd20b290de761738c029ad,__v: 0,id: '60aaa827ec89de07e0fb8db3'
}

但是如果我这样做：

 getParkingComplex: async (parent,{uuid}) => {
            const data = await ParkingComplexModel.findById(uuid)
             .populate('houses')
             .exec()
            console.log(data)
            return data;
        }

我得到了空的“房子”数组：

{
  isDeleted: false,houses: [],id: '60aaa827ec89de07e0fb8db3'
}

我做错了什么？感谢帮助！

解决方法

你会不会……因为你将房屋的默认返回值设置为一个空数组？

...
houses: [
            {
                type: Schema.Types.ObjectId,ref: 'House',default: () => {
                    return [];
                }
            }
        ],....