const arr = [1, 2, 3, [4], [5, 6], [7, 8, 9]];
console.log(arr.flat(1));

const deepArr = [1, [2, [3, 4], 5], [6, [7, 8], 9]]; // flat Methode stellt Werte eine Stufe höher um
console.log(deepArr.flat());

const account1 = {
  owner: "David Aster",
  movements: [200, 450, -400, 3000, -650, -130, 70, 1300],
  interestRate: 1.2, // %
  pin: 1111,
};

const account2 = {
  owner: "Joanne Aster",
  movements: [5000, 3400, -150, -790, -3210, -1000, 8500, -30],
  interestRate: 1.5,
  pin: 2222,
};

const account3 = {
  owner: "Steven Schmidt",
  movements: [200, -200, 340, -300, -20, 50, 400, -460],
  interestRate: 0.7,
  pin: 3333,
};

const account4 = {
  owner: "Elvis Presley",
  movements: [430, 1000, 700, 50, 90],
  interestRate: 1,
  pin: 4444,
};

const accounts = [account1, account2, account3, account4];

const accountsMovements = accounts.map(acc => acc.movements);
const allMovements = accountsMovements.flat(); // gibt alle Transaktionen aus allen Accounts zurück(extrahiert bestehende Transaktionen, die in den Felder sind)
const overallBalance = allMovements.reduce((acc, cur) => acc + cur); // Berechnung aller Transaktionen