Why Do we use Arrays?

If you have a list of flavours, storing the flavours in single variables could look like this:

let f1 = "Vanilla";
let f2 = "Strawberry";
let f3 = "Chocolate";

However, what if you want to loop through the flavours and find a specific one? And what if you had not 3 flavours, but 300?

The solution is an array!

Creating An array

There are two ways to create an array in javascript

1. Using an array literal

const flavours = [ "Vanilla", "Strawberry", "Chocolate"];

2.Using the JavaScript Keyword new

const flavours = new Array("Vanilla", "Strawberry", "Chocolate");

We can also create an array using javascript new keyword but it is not recommended as it provides unexpected results while declaring an array with single element.

Arrays in Javascript Vs Arrays in other languages

Array declaration in Java


int[] arr = new int[5]{1,2,3,4,5};

Array declaration in javascript

const person = ["John", "Doe", 46];

As you may have noticed in the above array declaration examples, you can see in other languages(JAVA or any other similar languages) , datatypes of all the array elements need to be same but in javascript datatypes of array elements can be different.

Accessing Array Elements

You access an array element by referring to the index number:

const person = ["John", "Doe", 46];

console.log(person[0]);

output

John

Some commonly used array methods

Method	Description
JavaScript Array length	Returns the number of elements in an array
JavaScript Array reverse()	Returns the array in reverse order
JavaScript Array sort()	Sorts the elements of an array in specific order
JavaScript Array fill()	Returns array by filling elements with given value
Javascript Array join()	Concatenates the array elements to a string
Javascript Array toString()	Returns the string representation of an array
JavaScript Array pop()	Removes and returns the last array element
JavaScript Array shift()	Removes and returns the first array element
JavaScript Array push()	Adds elements to end of array & returns its length
JavaScript Array unshift()	Adds elements to start of array and returns length
JavaScript Array concat()	Returns array by merging given value and/or arrays
JavaScript Array splice()	Returns an array by changing its elements in place
JavaScript Array lastIndexOf()	Returns the last index of occurrence of an element
JavaScript Array indexOf()	Returns the first index of occurrence of element
JavaScript Array of() Method	Creates a new Array instance from given arguments
JavaScript Array slice()	Returns a shallow copy of a portion of an array
JavaScript Array findIndex()	Returns index of element that satisfies condition
JavaScript Array find()	Returns first element that satisfies a condition
JavaScript Array includes()	Checks if a value exists in an array
Javascript Array reduce()	Reduces array to single value from left to right
Javascript Array isArray()	Checks if the given value is a JavaScript Array
Javascript Array filter()	Returns array by filtering elements on given test
JavaScript Array map()	Returns array by mapping elements using given func
Javascript Array forEach()	Executes the given function on array elements
Javascript Array some()	Tests if any element passes given test function

End

I hope you find this article helpful 😇

Thank you for your time and patience ❤️

To explore more,

you can go to this link - Mozilla Documentation for arrays

Arrays In JavaScript (A quick walkthrough)

This article will briefly explain you about java script arrays

Table of contents