First N Elements

Introduction

In this lab, we will explore how to use JavaScript to manipulate arrays and extract the first n elements of an array. We will use the slice() method to extract a portion of an array and return a new array with the extracted elements. Through this lab, you will learn how to implement the firstN function that extracts the first n elements of an array.

Skills Graph

How to Get the First N Elements of an Array in JavaScript

To get the first n elements of an array in JavaScript, you can use the Array.prototype.slice() method. Here's how:

const firstN = (arr, n) => arr.slice(0, n);

In this code snippet, arr represents the array you want to extract the elements from, and n represents the number of elements you want to extract. The slice() method takes two arguments: the start index (which is 0 in this case) and the end index (which is n). The method returns a new array containing the extracted elements.

Here's an example of how to use the firstN() function:

firstN(["a", "b", "c", "d"], 2); // ['a', 'b']

This will return the first two elements of the ['a', 'b', 'c', 'd'] array, which are ['a', 'b'].

Summary

Congratulations! You have completed the First N Elements lab. You can practice more labs in LabEx to improve your skills.