在 mongoose 中向下填充許多子文檔級別

Question

我正在創建一個評論系統，其中評論可以包含子評論（當您對評論發表評論時）。 我可以說我想填充 subComments 的深度，但我不知道預先有多少。 有沒有辦法告訴 mongoose 繼續填充已經填充的評論的子評論，直到沒有更多的子文檔？

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

請檢查圖形查找功能： https://docs.mongodb.com/manual/reference/operator/aggregation/graphLookup/

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