A brief example of how Array.prototype.reduce() can be used

useReduce.js

const transactions = [
    { id: 1, amount: 100 },
    { id: 2, amount: 200 },
    { id: 3, amount: 300 },
    { id: 4, amount: 450 }
]
const useReduce = transactions.reduce((acc, curr) => {
  return acc + curr.amount;
},0);

console.log("$" + useReduce.toLocaleString() + " paid");