Arrays in JavaScript

Arrays in JavaScript

Table of contents

The array is like a big container into which we can throw variables and later use them. It helps us to store multiple elements in a single variable using a single variable name. In JavaScript Array isn’t primitive, it’s an object.

Basic Array Operations and syntax

Creating an array :

const pets = ['Bruno' , 'Buddy' , 'Kuki' ]; 
//or we can also do,
const num = new Array (12 , 13 , 14) ;

To retrieve elements :

console.log(pets); //prints the whole array
console.log(pets[0]); //prints the first element , arrays are zero based

The .length property :

console.log(pets.length);  //prints 3 , length is calculated from 1 not 0
console.log(pets[pets.length-1]); //prints the last element of the array

We can also mutate the array using [ ],

pets[0] = 'Snowy'
console.log(pets); // 'Snowy' , 'Buddy' , 'Kuki'

Arrays also can store variables,

const firstName = 'Debasish'
const fullName = [ firstName , “Lenka” ]// prints Debasish Lenka

We can also include an array inside of an array,

const bio = [fullName , 'Job: Developer 🧑🏻‍💻'];


**0**: (2) ['Debasish', 'Lenka']
**1**: "Job: Developer 🧑🏻‍💻"
**length**: 2

push method(adds element to end of the array):

const boys = ['Biki','Gudu','Raj'];
console.log(boys) // 'Biki' , 'Gudu' , 'Raj' , 'Jay'

/*push function also reyturns the length of the new array. if we store the above push
function in a const and try to capture it */

const pushed = boys.push('Jay') 
console.log(pushed); // returns 4

unshift method(adds to the beginning of the array):

console.log(boys); // 'John' , 'Biki' , 'Gudu' , 'Raj' , 'Jay'

pop method (Remove element from end) :

console.log(boys); // 'John' , 'Biki' , 'Gudu' , 'Raj'

shift method (Remove element from beginning) :

console.log(boys); // 'Biki' , 'Gudu' , 'Raj'

indexOf method tells us in which position a certain element is in the array :

console.log(boys.indexOf('Biki')); // 0
console.log(boys.indexOf('Sky')); // -1

includes method (returns true if the element is present in the array and false if the element is not present in the array):

console.log(boys); // 'Biki' , 'Gudu' , 'Raj' , 2023
console.log(boys.includes('2023'));//false //because it's testing with strict equality and doesn't do Type Coercion

Array.reverse() :

const boys = ['Biki' , 'Gudu' , 'Raj'];
// output: 'Biki' , 'Gudu' , 'Raj'

const reversed = boys.reverse();
// output: 'Raj' , 'Gudu' , 'Biki'

// reverse is destructive , it changes the original array.
// output: 'Raj' , 'Gudu' , 'Biki'


There are a lot of other methods in JavaScript and we can always refer to MDN for the same ✨. I hope you found this article useful, if you need any help or want to give any suggestions please let me know in the comment section.

Feel free to contact me.

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