acme-prework.js

//instructions
//write the 4 functions below
//no third party libraries
//try not to use any forEach
//each function should be short and some functions can depend on other functions (hint no function should be more than 10 lines)

//list of products
var products = [
  {
    id: 1,
    price: 5,
    name: 'foo'
  },
  {
    id: 2,
    price: 3,
    name: 'bar' 
  },
  {
    id: 3,
    price: 9,
    name: 'bazz'
  }
];

//list of line items
var lineItems = [
   {
     productId: 1,
     quantity: 1
   },
   {
     productId: 1,
     quantity: 1
   },
   {
     productId: 2,
     quantity: 1
   },
   {
     productId: 3,
     quantity: 1
   },
];
//returns an object
//keys are the ids of products
//the values are the products themselves
function generateProductsMap(products){
    var result = products.reduce(function(obj,elem) {
                            key = elem.id;
                            obj[key] = elem;
                            return obj;
                            }, {});
    return result;
}

//returns an object
//keys are the ids of products
//value is the total revenue for that product
function salesByProduct(products, lineItems){
    var result = {};
    var newLineItems = lineItems.reduce(function(obj,elem) {
                                        key = elem.productId;
                                        if (!obj[key]) {
                                        obj[key] = elem;
                                        } else {
                                        obj[key].quantity = obj[key].quantity + elem.quantity;
                                        }
                                        return obj;
                                        }, {});
    
    var productsMap = generateProductsMap(products);
    
    for (var key in productsMap) {
        result[key] = productsMap[key].price * newLineItems[key].quantity;
    }
    
    return result;
}

//return the total revenue for all products
function totalSales(products, lineItems){
    var total = 0;
    var salesByItem = salesByProduct(products, lineItems);
    for (var key in salesByItem) {
        total = total + salesByItem[key];
    }
    return total;
}

//return the product responsible for the most revenue
function topSellerByRevenue(products, lineItems){
    var salesByItem = salesByProduct(products, lineItems);
    var productsMap = generateProductsMap(products);
    var maxSales = 0;
    var maxItem;
    for (var key in salesByItem) {
        if (salesByItem[key] > maxSales) {
            maxSales = salesByItem[key];
            maxItem = productsMap[key].name;
        }
    }
    return maxItem;
}
console.log(`generates product map - should be
{
  1:{
    id: 1,
    name: "foo",
    price: 5
  },
  2:{
    id: 2,
    name: "bar",
    price: 3
  },
  3:{
    id: 3,
    name: "bazz",
    price: 9
  }
}

`, generateProductsMap(products));
console.log(`sales by product - should be
  {
    1: 10,
    2: 3,
    3: 9
}`, salesByProduct( products, lineItems));
console.log('total sales - should be 22', totalSales( products, lineItems));
console.log('top seller by revenue', topSellerByRevenue(products, lineItems ));