How to get last N elements of an array in JavaScript

Today We’ll teach you how to retrieve the last N elements from an array in JavaScript today. Using JavaScript, there are several ways to extract the last N number of elements from an array.

We showed you how to get the first N number of elements from an array in the previous post. You may read a couple more articles on the Array.

Ways to get last N elements of an array

1. slice() method
2. splice() method

1. slice() method

We’ll use the slice() function to obtain the last 5 elements from an array in this method. To get the last 5 entries from the list, this is a very easy and preferred approach.

Example 1: Get the last 5 elements

const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

// get the last 5 elements
const n = 5;

const newArr = arr.splice(-n);
console.log(newArr);
// [6, 7, 8, 9, 10]

Example 2: Get the last 2 elements

const arr = [
  {
    userId: 1,
    id: 1,
    title: "delectus aut autem",
    completed: false
  },
  {
    userId: 2,
    id: 2,
    title: "quis ut nam facilis et officia qui",
    completed: false
  },
  {
    userId: 1,
    id: 3,
    title: "fugiat veniam minus",
    completed: false
  }
];

const n = 2;

const newArr = arr.splice(-n);
console.log(newArr);
/*
[
  {
    userId: 2,
    id: 2,
    title: "quis ut nam facilis et officia qui",
    completed: false
  },
  {
    userId: 1,
    id: 3,
    title: "fugiat veniam minus",
    completed: false
  }
]
*/

2. splice() method

We can also retrieve the last N number of entries from the list using the splice() method. However, the original array will be updated by eliminating the last N entries from the list.

Example 1: Get the last 5 elements and update original list

const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

// get the last 5 elements
const n = 5;

const newArr = arr.splice(-n);
console.log(newArr);
// [6, 7, 8, 9, 10]
console.log(arr);
// [1, 2, 3, 4, 5]

Example 2: Get the last 2 elements and update original list

const arr = [
  {
    userId: 1,
    id: 1,
    title: "delectus aut autem",
    completed: false
  },
  {
    userId: 2,
    id: 2,
    title: "quis ut nam facilis et officia qui",
    completed: false
  },
  {
    userId: 1,
    id: 3,
    title: "fugiat veniam minus",
    completed: false
  }
];

const n = 2;

const newArr = arr.splice(-n);
console.log(newArr);
/*
[
  {
    userId: 2,
    id: 2,
    title: "quis ut nam facilis et officia qui",
    completed: false
  },
  {
    userId: 1,
    id: 3,
    title: "fugiat veniam minus",
    completed: false
  }
]*/
console.log(arr);
/*
[
  {
    userId: 1,
    id: 1,
    title: "delectus aut autem",
    completed: false
  }
]
*/

That’s it for today.
Thank you for reading. Happy Coding..!!