Overview
The Products API provides functions for creating, reading, and deleting product records. All functions are asynchronous and return Promises.
addProduct()
Adds a new product to the database.
The price of the product. Will be converted to a number.
Resolves with the auto-generated ID of the new product
Implementation
export async function addProduct(name, price) {
return tx('products', 'readwrite', (s) => s.add({ name, price: Number(price) }));
}
Example Usage
import { addProduct } from './js/db.js';
// Add a product
const productId = await addProduct('Coffee', 3.99);
console.log(`Product added with ID: ${productId}`);
// Add multiple products
await addProduct('Tea', 2.99);
await addProduct('Sandwich', 5.50);
Error Handling
try {
await addProduct('Latte', 4.50);
} catch (error) {
console.error('Failed to add product:', error);
// Handle: database unavailable, transaction failed, etc.
}
- Transaction fails if database is unavailable
- Invalid price values are converted to
NaN
- Missing parameters result in incomplete records
getProducts()
Retrieves all products from the database.
Resolves with an array of product objects
Product Object Structure
{
id: number, // Auto-generated unique identifier
name: string, // Product name
price: number // Product price
}
Implementation
export async function getProducts() {
return tx('products', 'readonly', (s) => {
return new Promise((resolve) => {
const items = [];
s.openCursor().onsuccess = (e) => {
const cur = e.target.result;
if (cur) { items.push(cur.value); cur.continue(); }
else resolve(items);
};
});
});
}
Example Usage
import { getProducts } from './js/db.js';
// Get all products
const products = await getProducts();
console.log(products);
// [
// { id: 1, name: 'Coffee', price: 3.99 },
// { id: 2, name: 'Tea', price: 2.99 },
// { id: 3, name: 'Sandwich', price: 5.50 }
// ]
// Display products
products.forEach(product => {
console.log(`${product.name}: ₹${product.price}`);
});
// Check if products exist
if (products.length === 0) {
console.log('No products found');
}
Error Handling
try {
const products = await getProducts();
if (products.length === 0) {
console.log('Database is empty');
}
} catch (error) {
console.error('Failed to retrieve products:', error);
}
deleteProduct()
Deletes a product from the database by ID.
The ID of the product to delete. Will be converted to a number.
Resolves when the product is successfully deleted
Implementation
export async function deleteProduct(id) {
return tx('products', 'readwrite', (s) => s.delete(Number(id)));
}
Example Usage
import { deleteProduct, getProducts } from './js/db.js';
// Delete a product by ID
await deleteProduct(1);
console.log('Product deleted');
// Delete and verify
await deleteProduct(2);
const remaining = await getProducts();
console.log(`${remaining.length} products remaining`);
// Delete multiple products
const productIds = [3, 4, 5];
for (const id of productIds) {
await deleteProduct(id);
}
Error Handling
try {
await deleteProduct(999);
// Note: Succeeds even if product doesn't exist
console.log('Delete operation completed');
} catch (error) {
console.error('Failed to delete product:', error);
}
- Deleting a non-existent ID succeeds silently
- Invalid IDs are converted to numbers (may result in unexpected behavior)
- The operation is atomic within a transaction