Node.js 在mongoose虚拟属性中处理异步操作

见issue#1894及issue#5762

虚拟只是getter/setter，它们被认为是同步的

您可以改为添加自定义instance method.

E.g.("mongoose": "^7.2.1")

import mongoose from 'mongoose';
import { config } from '../../config';

mongoose.set('debug', true);

const userSchema = new mongoose.Schema({
    name: String,
});
userSchema.method('dept', async function () {
    console.log(this);
    // @ts-ignore
    const result = await mongoose.model('bill').aggregate([
        {
            $match: {
                $and: [{ 'user._id': this._id }, { balance: { $gt: 0 } }],
            },
        },
        {
            $group: { _id: null, total: { $sum: '$balance' } },
        },
    ]);
    return result[0].total;
});
const User = mongoose.model('user', userSchema);

const billSchema = new mongoose.Schema({
    balance: Number,
    user: userSchema,
});
const Bill = mongoose.model('bill', billSchema);

(async function main() {
    try {
        await mongoose.connect(config.MONGODB_URI);
        await Promise.all([User, Bill].map((m) => m.collection.drop()));
        // seed
        const [user1, user2] = await User.create([{ name: 'Nick' }, { name: 'Jack' }]);
        await Bill.create([
            { balance: 100, user: user1 },
            { balance: 200, user: user1 },
            { balance: 0, user: user1 },
            { balance: 50, user: user2 },
        ]);
        //@ts-ignore
        const dept = await user1.dept();
        console.log("Nick's dept: ", dept);
    } catch (error) {
        console.error(error);
    } finally {
        await mongoose.connection.close();
    }
})();

输出:

Mongoose: users.drop()
Mongoose: bills.drop()
Mongoose: users.insertOne({ name: 'Nick', _id: ObjectId("6498f33d24d77a71b4976083"), __v: 0 }, {})
Mongoose: users.insertOne({ name: 'Jack', _id: ObjectId("6498f33d24d77a71b4976084"), __v: 0 }, {})
Mongoose: bills.insertOne({ balance: 100, user: { name: 'Nick', _id: ObjectId("6498f33d24d77a71b4976083"), __v: 0 }, _id: ObjectId("6498f33d24d77a71b4976087"), __v: 0}, {})
Mongoose: bills.insertOne({ balance: 200, user: { name: 'Nick', _id: ObjectId("6498f33d24d77a71b4976083"), __v: 0 }, _id: ObjectId("6498f33d24d77a71b4976089"), __v: 0}, {})
Mongoose: bills.insertOne({ balance: 0, user: { name: 'Nick', _id: ObjectId("6498f33d24d77a71b4976083"), __v: 0 }, _id: ObjectId("6498f33d24d77a71b497608b"), __v: 0}, {})
Mongoose: bills.insertOne({ balance: 50, user: { name: 'Jack', _id: ObjectId("6498f33d24d77a71b4976084"), __v: 0 }, _id: ObjectId("6498f33d24d77a71b497608d"), __v: 0}, {})
{ name: 'Nick', _id: new ObjectId("6498f33d24d77a71b4976083"), __v: 0 }
Mongoose: bills.aggregate([ { '$match': { '$and': [ { 'user._id': new ObjectId("6498f33d24d77a71b4976083") }, { balance: { '$gt': 0 } } ] } }, { '$group': { _id: null, total: { '$sum': '$balance' } } }], {})
Nick's dept:  300