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How to get first N elements of an array in JavaScript

📅April 7, 2022|🗁JavaScript

In this tutorial, we’ll look at how to obtain the first N elements from an array in JavaScript. There are a few different ways to obtain N items from an array using JavaScript, but we’ll go through two of them.

  1. slice() method
  2. filter() method

1. slice() method

We’ll use the slice() function to obtain the top 5 elements from an array in this method. It’s the most convenient way to obtain stuff.

Example 1: Get the first 5 elements


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

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

const newArr = arr.splice(0, n);
console.log(newArr);
// [1, 2, 3, 4, 5]

Example 2: Get the first 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(0, n);
console.log(newArr);
/*
[
  {
    userId: 1,
    id: 1,
    title: "delectus aut autem",
    completed: false
  },
  {
    userId: 2,
    id: 2,
    title: "quis ut nam facilis et officia qui",
    completed: false
  }
]
*/

2. filter() method

We can also obtain the first N number of entries from the list using the filter() function. To filter the records, we’ll need to use the element index.

Example 1: Get the first 5 elements


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

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

const newArr = arr.filter((x, i) => i 

Example 2: Get the first 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.filter((x, i) => i 

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