CODEWITHSUNDEEP
javascriptnode.js
S. Farooq
S. Farooq

Reputation: 218

TypeError: Cannot read property 'price' of undefined

I am creating an online shop for learning node.js. When I delete a product from products.json file, respective products in the cart.json are also deleted. I get the following error in the picture when I try to delete a product. This is the code!

In products.ejs

<form action="/admin/delete-product" method="POST">
  <input type="hidden" name="productId" value="<%=product.id%>">
  <button class="btn" type="submit">Delete</button>
</form>

After linking controller, in the controller function I have In admin.js controller,

// import product model
const Product = require('../models/product');
// delete a product
exports.postDeleteProduct = (req, res) => {
  const prodId = req.body.productId;
  Product.deleteById(prodId, () => {
    res.redirect('/admin/products');
  });
}

Then in the product.js model, I have

// import cart model
const Cart = require('./cart');

// get all the products from the file

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

// delete by id

static deleteById(id, callback) {
    getProductsFromFile(products => {
      const product = products.find(prod => prod.id == id);
      const updatedProducts = products.filter(prod => prod.id !== id);
      fs.writeFile(p, JSON.stringify(updatedProducts), err => {
        if (!err) {
          console.log('Product: ',product);

          //also delete in the cart
          Cart.deleteProduct(id, product.price, callback);
        }
      })
    })
  }

Upon executing the code, I get the following error. Notice, how there are two console outputs for 'Product'. One for the actual Product and second undefined for some reason!

enter image description here

Upvotes: 0

Views: 890

Answers (1)

Callam
Callam

Reputation: 11539

static deleteById(id, callback) {
  console.log('deleteById', { id });
  getProductsFromFile(products => {
    let deletedProduct = null;
    let updatedProducts = [];

    for(const product of products) {
      if(product.id === id) {
        deletedProduct = product
      } else {
        updatedProducts.push(product);
      }
    }

    if (!deletedProduct) {
      console.log('deleteById: Product not found', { id });
      callback();
    } else {
      fs.writeFile(p, JSON.stringify(updatedProducts), err => {
        if (!err) {
          console.log('deleteById: Product', deletedProduct);
          Cart.deleteProduct(id, deletedProduct.price, callback);
        }
      });
    }
  })
}

Upvotes: 1

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