MongoDB按fighterId分组并转换购物车数据格式的技术需求

需求说明 #

在MongoDB中对用户购物车数据按fighterId进行分组，转换为指定的结构化格式，当用户请求查看购物车时返回该格式的数据。

用户信息模型（User Schema） #

const mongoose = require("mongoose");
const Schema = mongoose.Schema;

const userSchema = new Schema(
  {
    email: {
      type: String,
      required: true,
      unique: true,
    },
    password: {
      type: String,
      required: true,
    },
    userName: {
      type: String,
      unique: true,
    },
    firstName: {
      type: String,
    },
    lastName: {
      type: String,
    },
    currency: {
      type: String,
    },
    promotionCompany: {
      type: String,
    },
    displayNameInPublicRankingPage: {
      type: Boolean,
      default: false,
    },
    surpriceContribution: {
      type: Boolean,
      default: false,
    },
    surpriceContributionAmount: {
      type: String,
    },
    profileImage: {
      type: String,
    },
    bannerImage: {
      type: String,
    },
    setAutoPost: {
      type: Boolean,
      default: false,
    },
    agreeTermConditions: {
      type: Boolean,
      default: false,
    },
    status: {
      type: String,
      default: true,
    },
    role: {
      type: String,
      enum: ["fighter", "companion"],
      default: "fighter",
    },
    followers: [
      {
        type: mongoose.Schema.Types.ObjectId,
        ref: "User",
      },
    ],
    cart: [
      {
        shopType: {
          type: String,
          enum: ["goal", "surprise"],
          default: "goal",
        },
        goal: { type: mongoose.Schema.Types.ObjectId, ref: "Goal" },
        quantity: Number,
        goalType: String,
        amount: String,
        senderMessage: String,
        fighterId: String,
      },
    ],
    socialLinks: [
      {
        platform: {
          type: String,
          enum: [
            "Facebook",
            "Twitter",
            "Instagram",
            "LinkedIn",
            "Tiktok",
            "Other",
          ], // 根据需要调整
          required: true,
        },
        link: {
          type: String,
          required: true,
        },
        status: {
          type: Boolean,
          default: true,
        },
      },
    ],
  },
  {
    timestamps: true,
  }
);

module.exports = mongoose.model("User", userSchema);

目标信息模型（Goal Schema） #

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const goalSchema = new Schema({
      goalName: {
        type: String,
        required: true,
      },
      goalPrice: {
        type: Number,
        required: true,
      },
      goalType: {
        type: String,
        enum: ['single', 'subscription', 'crowd'],
        default: 'single', 
      },
      goalPurchaseType: {
        type: String,
        enum: ['single', 'multiple'],
        default: 'multiple', 
      },
      goalCategory: {
        type: String,
        required: true,
      },
      goalImage: {
        type: String, 
        required: true,
      },
      status: {
        type: String,
        enum: ['active', 'unactive'],
        default: 'active', 
      },
      creator: {
        type: Schema.Types.ObjectId,
        ref: 'User',
        required: true
      }
 
  },{
    timestamps: true,
});

module.exports = mongoose.model('Goal', goalSchema);

期望输出格式 #

{
  "cart": [
    {
      "wisher": {
        "wisher_id": "63325fa1743c2a0004f30b29",
        "name": "Goddess Mariah",
        "userName": "ineeddmariah",
        "profileImage": "https://wishtender.s3.amazonaws.com/images/profileImages/6df12e17-793c-4159-9fb3-3fa7af2d712f.png",
        "Wishercurrency": "USD"
      },
      "cartItem": [
        {
          "id": "cart_id",
          "goalType": "tip",
          "quantity": 1,
          "goalImage": "goal_image",
          "goalPurchaseType": "single",
          "goalName": "example_goal_name",
          "goalPrice": "209"
        }
      ]
    }
    // 可添加更多分组后的购物车项
  ]
}

实现方案 #

使用MongoDB聚合框架结合Mongoose查询，完成分组与格式转换：

Mongoose聚合查询代码 #

const mongoose = require('mongoose');
const User = require('./models/User');
const Goal = require('./models/Goal');

async function getFormattedCart(userId) {
  const result = await User.aggregate([
    // 匹配当前请求购物车的用户
    { $match: { _id: mongoose.Types.ObjectId(userId) } },
    // 展开购物车数组，方便逐个处理项
    { $unwind: "$cart" },
    // 关联Goal集合，获取目标详情
    {
      $lookup: {
        from: "goals",
        localField: "cart.goal",
        foreignField: "_id",
        as: "cart.goalDetails"
      }
    },
    // 展开关联后的目标详情数组
    { $unwind: "$cart.goalDetails" },
    // 按fighterId分组，聚合愿望者信息和对应购物车项
    {
      $group: {
        _id: "$cart.fighterId",
        wisher: {
          $first: {
            wisher_id: "$cart.fighterId",
            name: { $concat: ["$firstName", " ", "$lastName"] },
            userName: "$userName",
            profileImage: "$profileImage",
            Wishercurrency: "$currency"
          }
        },
        cartItem: {
          $push: {
            id: "$cart._id",
            goalType: "$cart.goalType",
            quantity: "$cart.quantity",
            goalImage: "$cart.goalDetails.goalImage",
            goalPurchaseType: "$cart.goalDetails.goalPurchaseType",
            goalName: "$cart.goalDetails.goalName",
            goalPrice: { $toString: "$cart.goalDetails.goalPrice" }
          }
        }
      }
    },
    // 移除不需要的_id字段
    {
      $project: {
        _id: 0,
        wisher: 1,
        cartItem: 1
      }
    },
    // 将分组结果包裹到cart数组中
    {
      $group: {
        _id: null,
        cart: { $push: "$$ROOT" }
      }
    },
    {
      $project: {
        _id: 0,
        cart: 1
      }
    }
  ]);

  return result.length > 0 ? result[0] : { cart: [] };
}

代码说明 #

1. $match：筛选出当前请求购物车的用户。
2. $unwind：将用户购物车数组拆分为单个文档，便于后续关联和分组操作。
3. $lookup：关联goals集合，拉取购物车项对应的目标详细信息。
4. $unwind：展开关联后的目标详情数组，确保每个购物车项对应一条完整的目标数据。
5. $group：按fighterId分组，聚合生成愿望者信息和该分组下的所有购物车项。
6. $project：调整字段结构，移除冗余的_id。
7. 最后两次聚合：将分组后的结果整理成期望的cart数组格式。

内容的提问来源于stack exchange，提问作者Rahul Kumar