node.js - 如何在嵌套文档中查找记录？

Question

所以我正在学习 mongoose 并实现了一个 Customer 模型，如下所示:

let CustomerSchema = new Schema({
    stripe_id: {
        type: String,
        required: true
    },
    telegram_id: {
        type: Number
    },
    email: {
        type: String,
        required: true
    },
    subscriptions: [SubscriptionSchema],
    created_at: {
        type: Date,
        default: Date.now,
        required: true
    }
});

本质上我想返回客户的所有订阅，但如何在嵌套文档中搜索，在本例中是订阅？

这是订阅模型:

let SubscriptionSchema = new Schema({
    status: {
        type: String,
        required: true
    },
    plan_id: {
        type: String,
        required: true
    }
});

我只想返回状态为有效的订阅，目前我可以通过以下方式搜索客户:

let customer = await CustomerModel.findOne({telegram_id: ctx.chat.id});

Answer 1

您可以使用filter聚合以在嵌套数组中进行过滤。

Playground

Mongoose 的快速路线示例:

router.get("/customers/:id", async (req, res) => {

  let result = await Customer.aggregate([
    {
      $match: {
        telegram_id: 1 //todo: req.params.id
      }
    },
    {
      $project: {
        _id: "$_id",
        stripe_id: "$stripe_id",
        telegram_id: "$telegram_id",
        email: "$email",
        subscriptions: {
          $filter: {
            input: "$subscriptions",
            as: "item",
            cond: {
              $eq: ["$$item.status", "active"]
            }
          }
        }
      }
    }
  ]);

 //todo: result will be an array, you can return the result[0] if you want to return as object
  res.send(result); 
});

假设我们有以下文档:

{
    "_id" : ObjectId("5e09eaa1c22a8850c01dff77"),
    "stripe_id" : "stripe_id 1",
    "telegram_id" : 1,
    "email" : "email@gmail.com",
    "subscriptions" : [
        {
            "_id" : ObjectId("5e09eaa1c22a8850c01dff7a"),
            "status" : "active",
            "plan_id" : "plan 1"
        },
        {
            "_id" : ObjectId("5e09eaa1c22a8850c01dff79"),
            "status" : "passive",
            "plan_id" : "plan 2"
        },
        {
            "_id" : ObjectId("5e09eaa1c22a8850c01dff78"),
            "status" : "active",
            "plan_id" : "plan 3"
        }
    ],
    "created_at" : ISODate("2019-12-30T15:16:33.967+03:00"),
    "__v" : 0
}

结果将是这样的:

[
    {
        "_id": "5e09eaa1c22a8850c01dff77",
        "stripe_id": "stripe_id 1",
        "telegram_id": 1,
        "email": "email@gmail.com",
        "subscriptions": [
            {
                "_id": "5e09eaa1c22a8850c01dff7a",
                "status": "active",
                "plan_id": "plan 1"
            },
            {
                "_id": "5e09eaa1c22a8850c01dff78",
                "status": "active",
                "plan_id": "plan 3"
            }
        ]
    }
]

如果您不想逐一投影项目，可以使用addFields像这样的聚合:

router.get("/customers/:id", async (req, res) => {
  let result = await Customer.aggregate([
    {
      $match: {
        telegram_id: 1
      }
    },
    {
      $addFields: {
        subscriptions: {
          $filter: {
            input: "$subscriptions",
            as: "item",
            cond: {
              $eq: ["$$item.status", "active"]
            }
          }
        }
      }
    }
  ]);

  res.send(result);
});