Tutorials References Exercises Videos Menu
Create Website Get Certified Upgrade

JS Tutorial

JS HOME JS Introduction JS Where To JS Output JS Statements JS Syntax JS Comments JS Variables JS Let JS Const JS Operators JS Arithmetic JS Assignment JS Data Types JS Functions JS Objects JS Events JS Strings JS String Methods JS String Search JS String Templates JS Numbers JS BigInt JS Number Methods JS Number Properties JS Arrays JS Array Methods JS Array Sort JS Array Iteration JS Array Const JS Dates JS Date Formats JS Date Get Methods JS Date Set Methods JS Math JS Random JS Booleans JS Comparisons JS If Else JS Switch JS Loop For JS Loop For In JS Loop For Of JS Loop While JS Break JS Iterables JS Sets JS Maps JS Typeof JS Type Conversion JS Bitwise JS RegExp JS Precedence JS Errors JS Scope JS Hoisting JS Strict Mode JS this Keyword JS Arrow Function JS Classes JS Modules JS JSON JS Debugging JS Style Guide JS Best Practices JS Mistakes JS Performance JS Reserved Words

JS Versions

JS Versions JS 2009 (ES5) JS 2015 (ES6) JS 2016 JS 2017 JS 2018 JS 2019 JS 2020 JS 2021 JS IE / Edge JS History

JS Objects

Object Definitions Object Properties Object Methods Object Display Object Accessors Object Constructors Object Prototypes Object Iterables Object Sets Object Maps Object Reference

JS Functions

Function Definitions Function Parameters Function Invocation Function Call Function Apply Function Bind Function Closures

JS Classes

Class Intro Class Inheritance Class Static

JS Async

JS Callbacks JS Asynchronous JS Promises JS Async/Await

JS HTML DOM

DOM Intro DOM Methods DOM Document DOM Elements DOM HTML DOM Forms DOM CSS DOM Animations DOM Events DOM Event Listener DOM Navigation DOM Nodes DOM Collections DOM Node Lists

JS Browser BOM

JS Window JS Screen JS Location JS History JS Navigator JS Popup Alert JS Timing JS Cookies

JS Web APIs

Web API Intro Web Forms API Web History API Web Storage API Web Worker API Web Fetch API Web Geolocation API

JS AJAX

AJAX Intro AJAX XMLHttp AJAX Request AJAX Response AJAX XML File AJAX PHP AJAX ASP AJAX Database AJAX Applications AJAX Examples

JS JSON

JSON Intro JSON Syntax JSON vs XML JSON Data Types JSON Parse JSON Stringify JSON Objects JSON Arrays JSON Server JSON PHP JSON HTML JSON JSONP

JS vs jQuery

jQuery Selectors jQuery HTML jQuery CSS jQuery DOM

JS Graphics

JS Graphics JS Canvas JS Plotly JS Chart.js JS Google Chart JS D3.js

JS Examples

JS Examples JS HTML DOM JS HTML Input JS HTML Objects JS HTML Events JS Browser JS Editor JS Exercises JS Quiz JS Certificate

JS References

JavaScript Objects HTML DOM Objects


JavaScript Array Methods


Converting Arrays to Strings

The JavaScript method toString() converts an array to a string of (comma separated) array values.

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits.toString();

Result:

Banana,Orange,Apple,Mango
Try it Yourself »

The join() method also joins all array elements into a string.

It behaves just like toString(), but in addition you can specify the separator:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits.join(" * ");

Result:

Banana * Orange * Apple * Mango
Try it Yourself »

Popping and Pushing

When you work with arrays, it is easy to remove elements and add new elements.

This is what popping and pushing is:

Popping items out of an array, or pushing items into an array.



JavaScript Array pop()

The pop() method removes the last element from an array:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.pop();
Try it Yourself »

The pop() method returns the value that was "popped out":

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
let fruit = fruits.pop();
Try it Yourself »

JavaScript Array push()

The push() method adds a new element to an array (at the end):

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.push("Kiwi");
Try it Yourself »

The push() method returns the new array length:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
let length = fruits.push("Kiwi");
Try it Yourself »

Shifting Elements

Shifting is equivalent to popping, but working on the first element instead of the last.


JavaScript Array shift()

The shift() method removes the first array element and "shifts" all other elements to a lower index.

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.shift();
Try it Yourself »

The shift() method returns the value that was "shifted out":

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
let fruit = fruits.shift();
Try it Yourself »

JavaScript Array unshift()

The unshift() method adds a new element to an array (at the beginning), and "unshifts" older elements:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.unshift("Lemon");
Try it Yourself »

The unshift() method returns the new array length:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.unshift("Lemon");
Try it Yourself »

Changing Elements

Array elements are accessed using their index number:

Array indexes start with 0:

[0] is the first array element
[1] is the second
[2] is the third ...

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits[0] = "Kiwi";
Try it Yourself »

JavaScript Array length

The length property provides an easy way to append a new element to an array:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits[fruits.length] = "Kiwi";
Try it Yourself »

JavaScript Array delete()

Warning !

Array elements can be deleted using the JavaScript operator delete.

Using delete leaves undefined holes in the array.

Use pop() or shift() instead.

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
delete fruits[0];
Try it Yourself »

Merging (Concatenating) Arrays

The concat() method creates a new array by merging (concatenating) existing arrays:

Example (Merging Two Arrays)

const myGirls = ["Cecilie", "Lone"];
const myBoys = ["Emil", "Tobias", "Linus"];

const myChildren = myGirls.concat(myBoys);
Try it Yourself »

The concat() method does not change the existing arrays. It always returns a new array.

The concat() method can take any number of array arguments:

Example (Merging Three Arrays)

const arr1 = ["Cecilie", "Lone"];
const arr2 = ["Emil", "Tobias", "Linus"];
const arr3 = ["Robin", "Morgan"];
const myChildren = arr1.concat(arr2, arr3);
Try it Yourself »

The concat() method can also take strings as arguments:

Example (Merging an Array with Values)

const arr1 = ["Emil", "Tobias", "Linus"];
const myChildren = arr1.concat("Peter"); 
Try it Yourself »

Splicing and Slicing Arrays

The splice() method adds new items to an array.

The slice() method slices out a piece of an array.


JavaScript Array splice()

The splice() method can be used to add new items to an array:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.splice(2, 0, "Lemon", "Kiwi");
Try it Yourself »

The first parameter (2) defines the position where new elements should be added (spliced in).

The second parameter (0) defines how many elements should be removed.

The rest of the parameters ("Lemon" , "Kiwi") define the new elements to be added.

The splice() method returns an array with the deleted items:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.splice(2, 2, "Lemon", "Kiwi");
Try it Yourself »

Using splice() to Remove Elements

With clever parameter setting, you can use splice() to remove elements without leaving "holes" in the array:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.splice(0, 1);
Try it Yourself »

The first parameter (0) defines the position where new elements should be added (spliced in).

The second parameter (1) defines how many elements should be removed.

The rest of the parameters are omitted. No new elements will be added.


JavaScript Array slice()

The slice() method slices out a piece of an array into a new array.

This example slices out a part of an array starting from array element 1 ("Orange"):

Example

const fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
const citrus = fruits.slice(1);
Try it Yourself »

Note

The slice() method creates a new array.

The slice() method does not remove any elements from the source array.

This example slices out a part of an array starting from array element 3 ("Apple"):

Example

const fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
const citrus = fruits.slice(3);
Try it Yourself »

The slice() method can take two arguments like slice(1, 3).

The method then selects elements from the start argument, and up to (but not including) the end argument.

Example

const fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
const citrus = fruits.slice(1, 3);
Try it Yourself »

If the end argument is omitted, like in the first examples, the slice() method slices out the rest of the array.

Example

const fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
const citrus = fruits.slice(2);
Try it Yourself »

Automatic toString()

JavaScript automatically converts an array to a comma separated string when a primitive value is expected.

This is always the case when you try to output an array.

These two examples will produce the same result:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits.toString();
Try it Yourself »

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits;
Try it Yourself »

Note

All JavaScript objects have a toString() method.


Finding Max and Min Values in an Array

There are no built-in functions for finding the highest or lowest value in a JavaScript array.

You will learn how you solve this problem in the next chapter of this tutorial.


Sorting Arrays

Sorting arrays are covered in the next chapter of this tutorial.

Complete Array Reference

For a complete Array reference, go to our:

Complete JavaScript Array Reference.

The reference contains descriptions and examples of all Array properties and methods.

Test Yourself With Exercises

Exercise:

Use the correct Array method to remove the last item of the fruits array.

const fruits = ["Banana", "Orange", "Apple"];
;

Start the Exercise