Mongoose：在 .populate({match}) 中使用 $or

Question

我已经建立了一个这样的数据库：

const listSchema = new mongoose.Schema({
    name: {
        type: String,
        required: true,
        trim: true
    },
    additionalInfo: {
      type: String,
      required: false
    },
    author: {
        required: true,
        type: mongoose.Schema.Types.ObjectId,
        ref: 'User'
    }
  })

  listSchema.virtual('vocs', {
    ref: 'Voc',
    localField: '_id',
    foreignField: 'list'
  })

  var List = mongoose.model('List', listSchema);

  module.exports = List;

---

const vocSchema = new mongoose.Schema({
    foreignLanguage: {
        type: String,
        required: true,
        trim: true
    },
    translationGerman: {
      type: String,
      required: true,
      trim: true
    },
    translationForeignLanguage: {
        type: String,
        required: true
    },
    difficulty: {
        type: Number,
        required: true
    },
    list: {
        required: true,
        type: mongoose.Schema.Types.ObjectId,
        ref: 'List'
    }
  })

  var Voc = mongoose.model('Voc', vocSchema);

  module.exports = Voc;

现在，我想要做的是：我想选择具有特定作者的所有列表，然后联系 vocs 并通过 translationGerman 和 translationForeignLanguage 过滤这些 vocs：我想选择所有列表中的所有 vocs有一个特定的值（假设存储“translationGerman”或“translationForeignLanguage”中的“apple”一词。我尝试了以下代码：

router.get('/api/filterAllWords/:wordname', auth, async (req, res) => {
    try {

        // const words = await Voc.find({$or:[{translationForeignLanguage: req.params.wordname},{translationGerman: req.params.wordname}]});
        // console.log(words);
        // res.send(words)

        const lists = await List.find({author: req.user._id});
        let allVocs = [];

        for (let i = 0; i < lists.length; i++) {
            const singleListVocs = await lists[i].populate(
                {path: "vocs",
                match: {
                    {$or:[{translationForeignLanguage: req.params.wordname},{translationGerman: req.params.wordname}]}
                }}).execPopulate();
            for(let i = 0; i < singleListVocs.vocs.length; i++) {
                allVocs.push(singleListVocs.vocs[i])
            }
        }

        res.send(allVocs)
    }

    catch {
        res.status(404).send({status: 'No vocs found'});
    }
})

当我尝试测试代码时，它会向我发送错误“Unexpected token”。我是否使用了 $or 里面的 populate(match) 错误。当我尝试重复此代码时，只需将“translationForeignLanguage: req.params.wordname”作为匹配参数，一切都很好，并且运行良好！

感谢您的帮助！

朱莉娅

Answer 1

只需去掉match （围绕$or 语句）中的额外花括号，它应该可以工作：

lists[i]
  .populate({
    path: 'vocs',
    match: {
      $or: [
        { translationForeignLanguage: req.params.wordname },
        { translationGerman: req.params.wordname },
      ],
    },
  })
  .execPopulate();