How to access nested elements of json object in node js and mongodb

Question

const mongoose = require("mongoose");

const productSchema = mongoose.Schema({
  product_name: {
    type: String,
    required: [true, "Must Enter Product Name"],
  },
  product_brand: {
    type: String,
  },
  category: {
    type: String,
    required: [true, "Must Enter Product Catagorey"],
  },
  reviews: [
    {
      name: {
        type: String,
      },
      user: {
        type: mongoose.Schema.Types.ObjectId,
        ref: "User",
      },
      comment: {
        type: String,
        required: true,
      },
      rating: {
        type: Number,
        // required: true,
      },
    },
    { timestamps: true },
  ],

  owner: {
    type: mongoose.Schema.Types.ObjectId,
    ref: "User",
  },
});

module.exports = mongoose.model("Product", productSchema);

Here I want to access the values of commet for Appling filters

Here is is the output of my products

[
  {
    "_id": "63c4ee520ca7722674d007d5",
    "product_name": "Headphones",
    "product_description": "xvy",
    "product_price": 8000,
    "product_brand": "Apple",
    "product_color": "White",
    "product_stoke": 3,
    "category": "Headphones",
    "product_image": "public\\images\\uploaded\\products\\167385045002297820433-5f2f-43d1-972a-4b33785393ee.0ad829318c5599f429d2a6e625f8bde3.jpeg",
    "product_sku": "#1",
    "owner": "63c4ed720ca7722674d007ab",
    "reviews": [
      {
        "name": "Daniyal Alam",
        "user": "63c43d54cf582066929c8c46",
        "comment": "Good Mobbile Phone",
        "rating": 4,
        "_id": "63cbce2cd52bf9ecfdf29323"
      }
    ],
    "__v": 1
  },
  {
    "_id": "63c4e3530ca7722674d006b6",
    "product_name": "Air bud Two.",
    "product_description": "In the busy world which is fil.",
    "product_price": 50000,
    "product_brand": "Apple",
    "product_color": "White",
    "product_stoke": 5,
    "category": "Headphones",
    "product_image": "public\\images\\uploaded\\products\\167384763581197820433-5f2f-43d1-972a-4b33785393ee.0ad829318c5599f429d2a6e625f8bde3.jpeg",
    "product_sku": "33",
    "owner": "63c4d8ac0ca7722674d00529",
    "reviews": [],
    "__v": 0
  },
]

I want to access my comments I tried the following code but it only returns reviews

exports.commentProduct = async (req, res, next) => {
  const newproduct = await Product.find({});
  try {
    const reviews = newproduct?.map((p) => {
      if (typeof p.reviews != "undefined") {
        console.log(p.reviews);
      }
    });
    const com = reviews?.map((c) => {
      // console.log(comments);
    });

    // const comments = reviews.comment;
    return res.status(200).json({
      success: true,
      reviews,
    });
  } catch (error) {
    return res.status(500).json({
      success: false,
      message: error.message,
    });
  }
};

the Console Prints products having reviews but after applying dot notation on reviews I got undefined

[
  {
    name: 'Daniyal Alam',
    user: new ObjectId("63c43d54cf582066929c8c46"),
    comment: 'BEst One',
    rating: 5,
    _id: new ObjectId("63cbce44d52bf9ecfdf29743")
  }
]
[]
[]
[]
[]
[]
[]
[]
[]
[
  {
    name: 'Daniyal Alam',
    user: new ObjectId("63c43d54cf582066929c8c46"),
    comment: 'pp',
    rating: 4,
    _id: new ObjectId("63c4f76e0ca7722674d040ae")
  }
]
[]
[
  {
    name: 'Daniyal Alam',
    user: new ObjectId("63c43d54cf582066929c8c46"),
    comment: 'Good Mobbile Phone',
    rating: 4,
    _id: new ObjectId("63cbce2cd52bf9ecfdf29323")
  }
]

Answer 1

Working with your example, you can map each item, then map the reviews, and get the comment out of each like using the following code

const data = [{ 
  "_id": "63c4ee520ca7722674d007d5",
  "product_name": "Headphones",
  "product_description": "xvy",
  "product_price": 8000,
  "product_brand": "Apple",
  "product_color": "White",
  "product_stoke": 3,
  "category": "Headphones",
  "product_image": "public\\images\\uploaded\\products\\167385045002297820433-5f2f-43d1-972a-4b33785393ee.0ad829318c5599f429d2a6e625f8bde3.jpeg",
  "product_sku": "#1",
  "owner": "63c4ed720ca7722674d007ab",
  "reviews": [{
    "name": "Daniyal Alam",
    "user": "63c43d54cf582066929c8c46",
    "comment": "Good Mobbile Phone",
    "rating": 4,
    "_id": "63cbce2cd52bf9ecfdf29323"
   }],
  "__v": 1 
}]

data.map((dat) => {
  dat["reviews"].map((rev) => {
    document.querySelector('div').innerHTML +=rev["comment"]
  })
})

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