CODEWITHSUNDEEP
javascriptnode.js
Piyush Mittal
Piyush Mittal

Reputation: 395

TypeError: Cannot read property 'price' of undefined at C:\NODEJS-COMPLETE-GUIDE\controllers\shop.js:45:37

I have trying to add my products in the cart and also trying to get the totalPrice but it shows error. Here, is My error:- enter image description here. Here, Is the code of my shop.js:-

exports.postCart = (req, res, next) => {
  const prodId = req.body.productId;
  Product.findById(prodId, product => {
    Cart.addProduct(prodId, product.price);
  });
  res.redirect('/cart');
};

Here, Is the code of cart.js file:-

const fs = require('fs');
const path = require('path');

const p = path.join(
    path.dirname(process.mainModule.filename),
    'data',
    'cart.json'
);

module.exports = class Cart {
    static addProduct(id, productPrice) {
        // Fetch the previous cart
        fs.readFile(p, (err, fileContent) => {
            let cart = { products: [], totalPrice: 0 };
            if (!err) {
                cart = JSON.parse(fileContent);
            }
            // Analyze the cart => Find existing product
            const existingProductIndex = cart.products.findIndex(
                prod => prod.id === id
            );
            const existingProduct = cart.products[existingProductIndex];
            let updatedProduct;
            // Add new product/ increase quantity
            if (existingProduct) {
                updatedProduct = { ...existingProduct };
                updatedProduct.qty = updatedProduct.qty + 1;
                cart.products = [...cart.products];
                cart.products[existingProductIndex] = updatedProduct;
            } else {
                updatedProduct = { id: id, qty: 1 };
                cart.products = [...cart.products, updatedProduct];
            }
            cart.totalPrice = cart.totalPrice + +productPrice;
            fs.writeFile(p, JSON.stringify(cart), err => {
                console.log(err);
            });
        });
    }
};

Here, Is the code of product.js file:-

const fs = require('fs');
const path = require('path');

const p = path.join(
    path.dirname(process.mainModule.filename),
    'data',
    'products.json'
);

const getProductsFromFile = cb => {
    fs.readFile(p, (err, fileContent) => {
        if (err) {
            cb([]);
        } else {
            cb(JSON.parse(fileContent));
        }
    });
};

module.exports = class Product {
    constructor(title, imageUrl, description, price) {
        this.title = title;
        this.imageUrl = imageUrl;
        this.description = description;
        this.price = price;
    }

    save() {
        this.id = Math.random().toString();
        getProductsFromFile(products => {
            products.push(this);
            fs.writeFile(p, JSON.stringify(products), err => {
                console.log(err);
            });
        });
    }

    static fetchAll(cb) {
        getProductsFromFile(cb);
    }

    static findById(id, cb) {
        getProductsFromFile(products => {
            const product = products.find(p => p.id === id);
            cb(product);
        });
    }
};

And If I remove the product.price from my shop.js file so it give me no error but when i add the price it gives me error.

Upvotes: 0

Views: 176

Answers (1)

Dipen Shah
Dipen Shah

Reputation: 26075

Looks like you are trying to add product to cart which wasn't found by findById method. Just add if condition in your callback to verify search result like.

exports.postCart = (req, res, next) => {
  const prodId = req.body.productId;
  Product.findById(prodId, product => {
    if (product) {    
      Cart.addProduct(prodId, product.price);
    } else {
      // log error or warn user
    }

  });
  res.redirect('/cart');
};

Upvotes: 1

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