Mongodb how to enforce a unique db reference id?

Question

Mongodb how to enforce a unique db reference id?

const LikeSchema = new mongoose.Schema({
    idOfPost: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'Post',
        required: true,
    },
    userWhoLiked: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'User',
        required: true,
        unique: true // This is not working? Why?
    },
    date=:{
        default: Date.now,
        required: true,
        type: Date,
    },

How can I make sure that all userWhoLiked fields are unique?

Answer 1

You should build a unique index, then in the case of an insert/update of a document with a duplicate userWhoLiked value you'll get duplicate key error thrown.