查找给出错误，因为尽管查询正确，但缺少 from

Question

对于使用 mongoose 的 mongo 中的 this 模型，查询如下：收到错误 MongoServerError: Missing ' from' 选项到 $lookup 阶段规范： { localField: "vendor",foreignField: "_id", as: "vendors" }

const items = await VendorItem.aggregate([
            {$lookup : { from: Vendor, localField: 'vendor', foreignField: "_id", as: "vendors"}},
            {$group: {categories: '$category'}}
        ]);