const people = [
  { name: "John", age: 25, city: "NYC" },
  { name: "Jane", age: 30, city: "LA" },
  { name: "Bob", age: 25, city: "NYC" },
  { name: "Alice", age: 30, city: "LA" }
];

// Group by age
const byAge = people.groupBy(person => person.age);
console.log(byAge);
// { 25: [{ name: "John", age: 25, city: "NYC" }, { name: "Bob", age: 25, city: "NYC" }],
//   30: [{ name: "Jane", age: 30, city: "LA" }, { name: "Alice", age: 30, city: "LA" }] }

// Group by city into a Map
const byCity = people.groupByToMap(person => person.city);
console.log(byCity); // Map with city keys

Array.prototype.toSorted

Returns a new sorted array without modifying the original.

const numbers = [3, 1, 4, 1, 5, 9];
const sorted = numbers.toSorted();
console.log(sorted); // [1, 1, 3, 4, 5, 9]
console.log(numbers); // [3, 1, 4, 1, 5, 9] (unchanged)

// With compare function
const users = [
  { name: "John", age: 30 },
  { name: "Jane", age: 25 },
  { name: "Bob", age: 35 }
];

const byAge = users.toSorted((a, b) => a.age - b.age);
console.log(byAge); // Sorted by age

Array.prototype.toReversed

Returns a new reversed array without modifying the original.

const arr = [1, 2, 3, 4, 5];
const reversed = arr.toReversed();
console.log(reversed); // [5, 4, 3, 2, 1]
console.log(arr); // [1, 2, 3, 4, 5] (unchanged)

Array.prototype.with

Returns a new array with the element at the given index replaced.

const arr = [1, 2, 3, 4, 5];
const newArr = arr.with(2, 10);
console.log(newArr); // [1, 2, 10, 4, 5]
console.log(arr); // [1, 2, 3, 4, 5] (unchanged)

// With negative index
const newArr2 = arr.with(-1, 100);
console.log(newArr2); // [1, 2, 3, 4, 100]