Javascript 如何在同一型号的子文档上使用Mongoose填充

首先，你想做的事情在populate美元是不可能实现的.这是因为模式声明中的ref属性用于引用模型，而不是路径.它用于告诉Mongoose您要使用哪个模型来执行$lookup，Mongoose希望该模型与您的数据库中的集合相对应.

其次，您在featureHeaders和features数组中使用的是productSchema中的子文档，因此populate无论如何都不适用于您.

谢天谢地，你可以解决这个问题，并得到populate为你工作.尽管您的命名约定和用例有点令人困惑，但希望这将有助于解释它是如何实现的:

1. FeatureHeader和Feature需要有自己的集合，而不是子文档，因此需要为它们创建模型.

import mongoose from "mongoose";
const featureHeaderSchema = new mongoose.Schema({
    header: {
        type: String,
        required: true,
    }
});
// You need create the FeatureHeader model
const FeatureHeader = mongoose.model("FeatureHeader", featureHeaderSchema);

const featureSchema = new mongoose.Schema({
    title: {
        type: String,
        required: true,
    },
    parentHeader: { 
       type: mongoose.Schema.Types.ObjectId, 
       ref: "FeatureHeader" //< Reference the FeatureHeader model
    }, 
    parentFeature: { 
       type: mongoose.Schema.Types.ObjectId, 
       ref: "Feature" //< You can reference the same model (i.e self)
    }
});
// You need create the Feature model
const Feature = mongoose.model("Feature", featureSchema);

const productSchema = new mongoose.Schema({
   title: {
      type: String,
      required: true,
   },
   thumbnail: String,
   description: String,
   manufacture: { 
      type: mongoose.Schema.Types.ObjectId, 
      ref: "User" //< Capitalise the model name
   },
   featureHeaders: [{
      type: mongoose.Schema.Types.ObjectId,
      ref: "FeatureHeader", //< Reference the FeatureHeader model
   }],
   features: [{
      type: mongoose.Schema.Types.ObjectId,
      ref: "Feature", //< Reference the Feature model
   }],
},
{ timestamps: true });
// You need create the Feature model
const Product = mongoose.model("Product", productSchema);

2. FeatureHeader和Feature需要分别保存在它们自己的集合中才能被引用.

const newFeatureOne = await Feature.create({
   title: 'Marvel',
});

const newFeatureHeader = await FeatureHeader.create({
   header: 'Superhero'
});

const newFeatureTwo = await Feature.create({
   title: 'Repulsor Beams',
   parentHeader: newFeatureHeader._id,
   parentFeature: newFeatureOne._id
});

const newProduct = await Product.create({
   title: 'Repulsor Beams',
   //...
   //... 
   featureHeaders: [newFeatureHeader._id],
   features: [newFeatureTwo._id],
});

3. 现在，您可以拨打populate将ObjectId替换为其相应的文档:

const id = req.body.id; //< Could be req.params.id or however you get the id

const product = await Product.findById(id)
   .populate("featureHeaders")
   .populate("features");

Note:根据您的设计和模型的作用域，您可能需要指定populate Options对象的path和/或model属性，如下所示:

const id = req.body.id; //< Could be req.params.id or however you get the id

const product = await Product.findById(id)
   .populate({path: "featureHeaders", model: "FeatureHeader"})
   .populate({path: "features", model: "Feature"});

希望所有这些都是有意义的，如果你有任何问题，请在 comments 中提问.