reduce
JavaScript
let orders = [
{ amount : 250 },
{ amount : 400 },
{ amount : 100 },
{ amount : 325 }
]
console.log(orders[0].amount);
console.log(orders);
let totals = orders.reduce(function(sum, order){
order.amount++;
console.log('inner', sum, order);
return sum + order.amount;
}, 0)
console.log(totals);
console.log(orders);