JSArray.js

let total = 0;
orders.forEach(order => total += order.value);
console.log(total);
///////////// Map function
let ordersWithShipping = orders.map(order => {
  order.shipping = calculateShipping(order);
  order.total = order.value + order.shipping;
  return order;
});

// The Hard One: Reduce. Tối ưu for
let orderTotal = orders.reduce((total, {value}) => total += value);


let orderIds = orders.map(order => { 
  return order.id;
});
// or fancier and better
let orderIds = orders.map(({id}) => id);

// Filter Function
let people = [
  {id: 1, name: "Ash", age: 10}, 
  {id: 2, name: "Sam", age: 23}, 
  {id: 3, name: "Shannon", age: 46},
  {id: 4, name: "Kim", age: 18}
];
let adults = people.filter(({age}) => age > 18);
// [ {id: 2, name: "Sam", age: 23}, 
//  {id: 3, name: "Shannon", age: 46}]

// Get name from filter result
let adultNames = people.filter(({age}) => age > 18)


  .map(({name}) => name);