为什么我不能填充猫鼬

Question

我正在尝试从用户模型获取填充数据。但是，人口没有工作。 我期待用户模型提供Cat数据。用户中没有猫数据。

这是我的猫模式。

const mongoose = require('mongoose');

const catSchema = new mongoose.Schema({
  name: {
    type: String,
    required: true,
  },
  accessibility: {
    type: String,
    required: true,
  },
  friendliness: {
    type: String,
    required: true,
  },
  likes: [{
    type: mongoose.Schema.Types.ObjectId,
    ref: 'User',
  }],
  founder: {
    type: mongoose.Schema.Types.ObjectId,
    ref: 'User',
    required: true,
  },
  comments:[{
    type: mongoose.Schema.Types.ObjectId,
    ref: 'Comment',
  }],
  location: [],
  image: {
    type: String,
    required: true,
  },
  time: {
    type: String,
  },
  description: {
    type: String,
    default: '',
  }
});

module.exports = mongoose.model('Cat', catSchema);

这是我的用户架构。

const mongoose = require('mongoose');

const userSchema = new mongoose.Schema({
  facebookId: {
    type: String,
    required: true,
  },
  name: {
    type: String,
    required: true,
  },
  cats: [{
    type: mongoose.Schema.Types.ObjectId,
    ref: 'Cat',
  }],
});

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

并且我使用这段代码来获取填充数据，但是它不起作用

  const user = await User.findById(id).populate('Cat');