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JavaScript JavaScript Array Iteration Methods Combining Array Methods Combining filter() and reduce()

Posted by Cole Smith
.a{fill-rule:evenodd;}techdegree
Cole Smith
Web Development Techdegree Student 13,796 Points

how do I complete this callback function?

I cant tell if I'm using the right properties to accurately use these callback methods. I think I'm somewhat close but any hints would be appreciated, thanks.

app.js 
const purchaseItems = [
    {
        name: 'apples',
        dept: 'groceries',
        price: 2.49
    },
    {
        name: 'bread',
        dept: 'groceries',
        price: 2.99
    },
    {
        name: 'batteries',
        dept: 'electronics',
        price: 5.80
    },
    {
        name: 'eggs',
        dept: 'groceries',
        price: 3.99
    },
    {
        name: 't-shirts',
        dept: 'apparel',
        price: 9.99
    }
];
let groceryTotal;

// groceryTotal should be: 9.47
// Write your code below
groceryTotal = purchaseItems 
  .filter(grocItem => grocItem.dept === 'groceries')
  .reduce((sum, grocItem) => sum + grocItem // this is where im stuck...) ;

console.log(groceryTotal);

1 Answer

Steven Parker
Steven Parker
229,732 Points
Steven Parker
Steven Parker
229,732 Points

Yes, you were pretty close! But remember that after the filter, you still have an array of item objects, but you want to sum only their prices. Plus, you'll need to provide 0 for the initial value of sum:

//                                         👇 only sum prices
  .reduce((sum, grocItem) => sum + grocItem.price, 0);
//                                                 👆 starting with 0
Cole Smith
.a{fill-rule:evenodd;}techdegree
Cole Smith
Web Development Techdegree Student 13,796 Points

ok thanks Steven for clarifying. that's what it was, I had trouble figuring out how to solely add the prices , I always overthink these challenges ha. thank you for your help!