#Pattern #OOP Icey Factory

inheritance.js

// how to do inheritance
// passing in the prototype function
// Object.freeze make only shallow copies

function makeProductList({ productDb }) {
  return Object.freeze({
    addProduct,
    empty,
    getProducts,
    removeProduct,
    // others
  )}
 
  // definitions for 
  // addProduct, etc…
}
                       
function makeShoppingCart(productList) {
  return Object.freeze({
    items: productList,
    someCartSpecificMethod,
    // …
)}
function someCartSpecificMethod () {
  // code 
  }
}
  
const productDb = []
const productList = makeProductList({ productDb })
const cart = makeShoppingCart(productList)

cart.items.addProduct()

snippet.js

// return on top to make a summary
// no need to use this and class syntax
// object composition

export default function makeShoppingCart({
  db
}) {
  return Object.freeze({
    addProduct,
    empty,
    getProducts,
    removeProduct,
    // others
  })
  function addProduct (product) {
    db.push(product)
  }
  
  function empty () {
    db = []
  }
  function getProducts () {
    return Object
      .freeze([...db])
  }
  function removeProduct (id) {
    // remove a product
  }
  // other functions
}
// someOtherModule.js
const db = []
const cart = makeShoppingCart({ db })
cart.addProduct({ 
  name: 'foo', 
  price: 9.99
})