how do I validate an update method in mongoose schema?

Question

I am trying to validate my update method using mongoose custom validators but my validation fails regardless of the data I send in.

Schema:

const TodoSchema = new mongoose.Schema({
    title: {
        type: String,
        validate: {
            validator: async function(title){
                const user = await this.constructor.findOne({title})
                if(user){
                    if(this.id === user.id){
                        return true
                    } return false
                } return true

            },
            message: props => `"${props.value}" already exists`
        },
        required: [true, "Title cannot be empty"]
    },
    description: {
        type: String,
    }
})

update Controller:

async function editItemPagePost(request, response){
    try {
        await TodoModel.findOneAndUpdate(
            {_id: request.params.id}, 
            {_id: request.params.id, title: request.body.title, description: request.body.description},
            { runValidators: true, context: 'query' }
        )

        response.redirect("/")

    } catch (error) {
        response.send(error)
    }

}

error:

{
    "errors": {
        "title": {
            "name": "ValidatorError",
            "message": "this.constructor.findOne is not a function",
            "properties": {
                "message": "this.constructor.findOne is not a function",
                "type": "user defined",
                "path": "title",
                "value": "item 2",
                "reason": {}
            },
            "kind": "user defined",
            "path": "title",
            "value": "item 2",
            "reason": {}
        }
    },
    "_message": "Validation failed",
    "name": "ValidationError",
    "message": "Validation failed: title: this.constructor.findOne is not a function"
}

I've tried using the pre-hook validator to automatically validate, but it didn't work either.

Does anyone know why it doesn't work?

Answer 1

Apparently, the "this" keyword works differently within the update method documentation. So I ended up changing my code as follows.

const TodoSchema = new mongoose.Schema({
    title: {
        type: String,
        validate: {
            validator: async function(title) {
                const model = await TodoModel.findOne({title})
                if(model){
                    if(this.id === model.id){
                        return true
                    } return false
                } return true

            },
            message: props => `"${props.value}" already exists`
        },
        required: [true, "Title cannot be empty"]
    },
    description: {
        type: String,
    }
})