如何在模式中的mongoose对象数组中添加虚拟字段？

yhuiod9q 于 2023-08-06 发布在 Go

关注(0)|答案(1)|浏览(99)

我有一个mongoose模式如下

const mongoose = require("mongoose");
const PostSchema = new mongoose.Schema(
  {
    title:{
        type:String,
        required: true,
        trim: true
    },
    author:{
      type: mongoose.Schema.Types.ObjectId,
      ref:'Customer'
    },
    images: [
        {img :{type:String}}
    ]
  },
  { timestamps: true }
);

PostSchema.virtual("images.imgCrop").get(function () {
   return `${this.img}/crop/720/720`;
 });
module.exports = mongoose.model("Post", PostSchema);

字符串
数据结果为

[
    {
        "_id": "64cb808d95a1ec6708a8e5e6",
        "title": "First Post",
        "images": [],
        "createdAt": "2023-08-03T10:33:31.253Z",
        "updatedAt": "2023-08-03T10:33:31.253Z",
        "__v": 0
    },
    {
        "_id": "64cb829a95a1ec6708a8f9ab",
        "title": "Next Post",
        "images": [
            {
                "_id": "64cb829a95a1ec6708a8f9ac",
                "img": "image001.png"
            },
            {
                "_id": "64cb829a95a1ec6708a8f9ad",
                "img": "image002.png"
            },
            {
                "_id": "64cb829a95a1ec6708a8f9ae",
                "img": "image003.png"
            }
        ],
        "createdAt": "2023-08-03T10:34:02.173Z",
        "updatedAt": "2023-08-03T10:34:02.173Z",
        "__v": 0
    }
]

型
在数据库中我已经有一堆数据，所以我需要在返回查询中修改新的图像路径为imgCrop：“image003.png/crop/720/720”
有没有可能使用mongoose virtual来实现这个功能？
数据提取如下
let posts = await Post.find（{}）.lean（）.populate（'author '）
所以结果应该如下

[
    {
        "_id": "64cb808d95a1ec6708a8e5e6",
        "title": "First Post",
        "images": [],
        "createdAt": "2023-08-03T10:33:31.253Z",
        "updatedAt": "2023-08-03T10:33:31.253Z",
        "__v": 0
    },
    {
        "_id": "64cb829a95a1ec6708a8f9ab",
        "title": "Next Post",
        "images": [
            {
                "_id": "64cb829a95a1ec6708a8f9ac",
                "img": "image001.png",
                "imgCrop": "image001.png/crop/720/720"
            },
            {
                "_id": "64cb829a95a1ec6708a8f9ad",
                "img": "image002.png",
                "imgCrop": "image002.png/crop/720/720"
            },
            {
                "_id": "64cb829a95a1ec6708a8f9ae",
                "img": "image003.png",
                "imgCrop": "image001.png/crop/720/720"
            }
        ],
        "createdAt": "2023-08-03T10:34:02.173Z",
        "updatedAt": "2023-08-03T10:34:02.173Z",
        "__v": 0
    }
]

型

mongoose

来源：https://stackoverflow.com/questions/76834999/how-to-add-a-virtual-field-to-mongoose-array-of-objects-in-a-schema

1条答案

按热度按时间

bvhaajcl1#

您需要提取ImageSchema并在其上声明一个virtual。

const ImageSchema = new mongoose.Schema({
  img: { type:String }
});
ImageSchema.virtual('imgCrop').get(function() {
  return `${this.img}/crop/720/720`;
});

const PostSchema = new mongoose.Schema(
  {
    title:{
        type: String,
        required: true,
        trim: true
    }
    images: [ImageSchema]
  },
  { timestamps: true }
);

字符串
请注意，在使用lean()查询时不会调用虚拟对象。
因此，您需要删除lean()或安装并使用mongoose-lean-virtuals插件：

const mongooseLeanVirtuals = require('mongoose-lean-virtuals');

PostSchema.plugin(mongooseLeanVirtuals);
// Maybe also add this? ImageSchema.plugin(mongooseLeanVirtuals);

Post.find({}).lean({ virtuals: true }).populate('author')

型

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如何在模式中的mongoose对象数组中添加虚拟字段？

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