在 mongoose 中向下填充许多子文档级别

Question

我正在创建一个评论系统，其中评论可以包含子评论（当您对评论发表评论时）。 我可以说我想填充 subComments 的深度，但我不知道预先有多少。 有没有办法告诉 mongoose 继续填充已经填充的评论的子评论，直到没有更多的子文档？

CommentModel.js

const mongoose = require("mongoose");
const schema = mongoose.Schema;

const commentSchema = new schema(
  {
    post: { type: schema.Types.ObjectId, required: true, ref: "post" },
    content: { type: String, required: true },
    votes: { type: Number, required: true },
    user: { type: schema.Types.ObjectId, required: true, ref: "user" },
    subComments: [{ type: schema.Types.ObjectId, ref: "comment" }],
    parentComment: { type: schema.Types.ObjectId, ref: "comment" },
  },
  { timestamps: true }
);

module.exports = Comment = mongoose.model("comment", commentSchema);

PostRouter.js

router.get("/full/:postId", async (req, res) => {
  const postId = req.params.postId;

  const post = await Post.findById(postId).populate({
    path: "comments",
    populate: {
      path: "subComments",
    },
    // how can i populate infinitely down in the path subComments?
  });

  res.json(post);
});

Answer 1

请检查图形查找功能： https://docs.mongodb.com/manual/reference/operator/aggregation/graphLookup/

arrays 的例子可以在这里找到： https://www.oodlestechnologies.com/blogs/how-to-use-graphlookup-in-mongodb/