Yogesh Chauhan's Blog

How to merge arrays in JavaScript?

in JavaScript on November 16, 2020

We can use concat() method to merge one or more than one arrays.

The concat() method creates a new array by merging, or concatenating, existing arrays.

Syntax


const array2 = array1.concat(arrays / values)

The concat() method creates a new array consisting of the elements in the object on which it is called.

It keeps adding the arrays elements in the same order as the arrays in arguments OR it values in the same order as arguments. 

Examples

Merging 2 Arrays


var names1 = ["Yogesh", "John"];
var names2 = ["Yogi", "Jonny"];
var names = names1.concat(names2);
console.log(names);

// [ 'Yogesh', 'John', 'Yogi', 'Jonny' ]

You can concat strings and numbers as well.


var names1 = ["Yogesh", "John"];
var names2 = [2, 3, 4];
var names = names1.concat(names2);
console.log(names);

// [ 'Yogesh', 'John', 2, 3, 4 ]

💡 concat() method change the existing arrays but returns a new array.

Merge Nested Arrays


const array1 = [["Yogesh"]];
const array2 = ["Jon", [2]];

const array = array1.concat(array2);

console.log(array);

// [ [ 'Yogesh' ], 'Jon', [ 2 ] ]

Merging 3 Arrays


var names1 = ["Yogesh", "John"];
var names2 = ["Yogi", "Jonny"];
var names3 = ["Yog", "Jon"];
var names = names1.concat(names2, names3);
console.log(names);

// [ 'Yogesh', 'John', 'Yogi', 'Jonny', 'Yog', 'Jon' ]

As we can see, all we need to do is just pas another array in the arguments. We can pass any number of arguments.

Passing a string as an argument


var names1 = ["Yogesh", "John"];
var names = names1.concat("Yog");
console.log(names);

// [ 'Yogesh', 'John', 'Yog' ]

It works like push() method. Isn’t it? JavaScript is full of surprises.


Most Read

#1 How to check if radio button is checked or not using JavaScript? #2 Solution to “TypeError: ‘x’ is not iterable” in Angular 9 #3 How to add Read More Read Less Button using JavaScript? #4 How to uninstall Cocoapods from the Mac OS? #5 PHP Login System using PDO Part 1: Create User Registration Page #6 How to Use SQL MAX() Function with Dates?

Recently Posted

#Aug 15 Is PHP still good for back-end programming? #Aug 10 How to create a multisite network in WordPress? #Aug 3 How to create a circle that follows a cursor using JavaScript and CSS? #Aug 3 How to make a curtain slider using jQuery and CSS? #Aug 2 How to progressively load images and add a blurry placeholder? #Aug 1 How to create a placeholder loader (throbber) using CSS?
You might also like these
How to modify navigation menus in WordPress?WordPressWordPress get_posts ExamplesWordPressHow to select multiple values in React dropdown?ReactHow to Find the Highest (or Lowest) Number in an Array in JavaScript?JavaScriptList of social media icon logo color codes in HEXMiscellaneousHow to Remove PHP File Extensions From Your Website URLs?PHP