CODEWITHSUNDEEP
javascriptnode.jsmongodbmongoose
Dom the Dev
Dom the Dev

Reputation: 23

Sort referenced Schema by created at date in Mongoose

following Problem, In my app i have Posts and each post can have an array of comments. I am trying to sort the comments by their date. I already searched for and already tried out any of the solutions but none of them worked for me.

My attempts not working:

const post = await Post.findById(id)
    .populate({
        path: 'comments',
        options: { sort: { createdAt: -1 } },
    })

const post = await Post.findById(id)
        .sort({ 'comments.createdAt': -1 })

In my Post Model if reference the Comments model like following:

COMMENT SCHEMA

    {
        comment: { type: String, required: true },
        user: {
            type: mongoose.Schema.Types.ObjectId,
            required: true,
            ref: 'User',
        },
    },
    { timestamps: true }
)

POST MODEL:

const postSchema = mongoose.Schema(
    {
        user: {
            type: mongoose.Schema.Types.ObjectId,
            required: true,
            ref: 'User',
        },
        image: {
            type: String,
        },
        text: {
            type: String,
            required: true,
        },
        workout: {
            type: mongoose.Schema.Types.ObjectId,
            ref: 'Workout',
        },
        comments: [commentSchema],
        numComments: {
            type: Number,
            required: true,
            default: 0,
        },
        likes: [likeSchema],
        numLikes: {
            type: Number,
            required: true,
            default: 0,
        },
    },
    {
        timestamps: true,
    }
)

Thx for any help in advance

Upvotes: 2

Views: 258

Answers (1)

Boris Kukec
Boris Kukec

Reputation: 721

The question is where you want to sort happen, to sort it on client side the easiest solution will be in place sorting of array comments, since you are not referencing another schema document with ref there is no need for populate (lookup), just write another then function like this:

    const post = await Post.findById(p._id).then(result => {
        result.comments.sort((a, b) => a.createdAt > b.createdAt ? -1 : 1);
        return result;
    })

To sort while fetching you should use the aggregate model function, and use the pattern of pipe stages: $match, $unwind, $sort, $group. But it is a way complicated.

Upvotes: 1

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