Push an object into array if not already present, otherwise update

Question

In a node.js server based on express, interacting with a mongo db through mongoose, I would like to insert a 'review' on 'reviews' array only if the user(identified by his id) hasn't reviewed the product yet, otherwise, update the review previously inserted. Given the following mongo schemes:

Product:

var ProductSchema = new Schema({
  ownerId: {
    type: Schema.ObjectId,
    required: 'Owner of recharge point required'
  },
  name: {
    type: String,
    required: 'The name is required'
  },      
  description: {
    type: String
  },
  reviews: {
    type: [Review]
  }
});

Review:

  var ReviewSchema = new Schema({
  reviewerId: {
    type: ObjectId,
    required: 'Reviewer id required',
    ref: 'User' <not showed>
  },
  review: {
    type: String
  },
  date: {
    type: Date, 
    default: Date.now
  }
});

That's the result I came up with, but this only insert new reviews, it doesn't update them yet. I think my solution could be improved (and simplified) a lot.

exports.review_product = function (req, res) {
    const review = req.body.review;
    const reviewerId = req.body.reviewerId;
    const productId = req.params.productId;

    Product.findOne({_id: productId}, function(error, result){
          if(error) {
               res.status(500).send({message: error}).end()
           } else if(result){
               var newReview = new Review({ reviewerId: reviewerId, review: review});
               Product.findOneAndUpdate({ _id: productId, 'reviews.reviewerId': { $ne: reviewerId }}, 
                 { $push: { 'reviews': newReview}},
                 function(error, found) {
                     if (error) {
                        res.status(500).send({message: error}).end()
                     } else if(found) {
                        res.status(200).send({message: 'Review succefully added.'}).end()
                     } else {
                        res.status(404).send({message: 'You already reviewed this product'}).end()
                     }
              });
           } else {
               res.status(404).send({message: 'Cannot find the product to be reviewed.'}).end()
           }
  })
};

Jay Kariesch · Accepted Answer · 2019-10-09 12:55:14Z

The best approach would be make a query with mongoose to check the product for the reviewer id before anything else. You can also make your code a bit more readable using async/await.

It would likely look something like (please note this is pseudo code):

exports.reviewProduct = async (req, res) => {
    const review = req.body.review;
    const reviewerId = req.body.reviewerId;
    const productId = req.params.productId;

    const hasReviewed = await Product.find({_id: productId, 'reviews.reviewerId': { $eq: reviewerId } )

    if(hasReviewed) {
        Product.findOneAndUpdate({
            _id: productId, 
            reviews: { $elemMatch: { reviewerId: reviewerId } }
            },
            { $set: {
                'review.$.title': review.title,
                'review.$.body': review.body
             }},
             {'new': true, 'safe': true, 'upsert': true})
    } else {
        Product.findOneAndUpdate(
            { _id: productId }, 
            { $push: { reviews: review } },
            {safe: true, upsert: true, new : true},
            (err, model) => {
               console.log(err);
            })
    }
}

Nicolas Losson · Accepted Answer · 2019-10-08 17:24:24Z

0

You can use the function includes()

For example:

var array = ["a","b","c"];
console.log(array.includes("a"); //return true
console.log(array.includes("z"); //return false because is not exist

Just adapt it to your code by replacing the variable string by your object

answered Oct 8, 2019 at 17:24

Nicolas Losson

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Push an object into array if not already present, otherwise update

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