accumulator-figure3.ts

const numbers: number[] = [3, 5, 7, 9, 12];

const accumulated = numbers.reduce(
    (accumulator: number, number: number) => accumulator + number,
   0);

// 36

const days = [
    "Sunday",
    "Monday",
    "Tuesday",
    "Wendesday",
    "Thursday",
    "Friday",
    "Saturday"
];

const week = days.reduce(
    (accumulator: { [dayOfWeek: string]: number }, day: string, index: number) => {
        return {
            ...accumulator,
            [day]: index
        }
    },
  {});

// {
//   Sunday: 0,
//   Monday: 1,
//   Tuesday: 2,
//   Wendesday: 3,
//   Thursday: 4,
//   Friday: 5,
//   Saturday: 6
// }