How to Convert Map to Array in JavaScript

This tutorial will show you how to convert a Map object’s keys, values, or key/value pairs to an Array object in JavaScript.

Published Categorized as JavaScript, Web & Code

In JavaScript, you can store key/value pairs in a Map while remembering the original order of insertion of each key.

For example, the code below creates a groceriesMap variable holding a Map object with the names of fruits and vegetables as the keys and their weight as the values:

groceriesMap = new Map();

groceriesMap.set('tomatoes', 500);
groceriesMap.set('cucumbers', 250);
groceriesMap.set('peppers', 250);

If you were to read the contents of the newly-created groceriesMap variable, you would see the following object:

Holding these values in a Map object is useful for many reasons. But what if, for the purposes of your application, you need them in an array instead?

This guide will show you how to convert Map values to an Array in JavaScript.

How to Convert Map Keys to an Array

To convert Map values to an Array, use the Array.from method to create a new array. Then store the keys in the newly-created array object using the Map.prototype.keys method.

Here’s what this looks like in terms of code:

groceriesArray = Array.from(groceriesMap.keys());

And here’s what you would see if you were to read the contents of the newly-created Array:

How to Convert Map Values to an Array

To convert Map values to an Array, use the Array.from method to create a new array. Then store the values in the newly-created array object using the Map.prototype.values method.

Here’s what this looks like in terms of code:

groceriesArray = Array.from(groceriesMap.values());

And here’s what you would see if you were to read the contents of the newly-created Array:

How to Convert a Map’s Key/Value Pairs to an Array of Objects

To convert a Map object’s key/value pairs to an Array of objects, use the Array.from method to create a new array. Then use an arrow function to store each key/value pair in that array:

groceriesArray = Array.from(groceriesMap, ([name, value]) => ({ name, value }));

And here’s what you would see if you were to read the contents of the newly-created Array of objects:

By Dim Nikov

Content creator with marketing and web development skills to pay the bills.

1 comment

Leave a comment

Your email address will not be published. Required fields are marked *