Interpolate a JavaScript variable for an object key

Learn how to interpolate a JavaScript variable for an object key for dynamic keys in a JavaScript object.

In JavaScript programming, a common requirement is the ability to use dynamic keys in objects. This article will provide a comprehensive guide on how to handle such scenarios effectively.


A basic understanding of JavaScript and familiarity with the concept of JavaScript objects is needed to fully grasp the methods discussed in this article.


The primary aim is to elucidate two different methods of using dynamic keys when working with JavaScript objects.

Step-by-Step Guide

Method 1: Initializing an Object with Dynamic Keys

Initially, you may find yourself working with a simple object with static key-value pairs, as shown below:

const args = { 	StaticKey: "some value" }

However, when a dynamic key is needed, the following approach can be employed. For this example, a constant with the string value DynamicKey is created.

const someKey = "DynamicKey"

Next, this constant is used as a key in our object, replacing the static DynamicKey.

const myDynamicObject = { 	[someKey]: "some value" };

In this instance, the key is surrounded by square brackets ([ ]). This syntax instructs JavaScript to treat the enclosed variable as the key's value.

An output of the object would appear as follows:

const someKey = "DynamicKey" ;
const myDynamicObject = { 	[someKey]: "some value" };  
console.log(myDynamicObject); // {DynamicKey: "some value"}

Method 2: Adding Dynamic Key-Value Pairs to Existing Object

Once myDynamicObject is defined and DynamicKey has been established, another key-value pair can be added to the existing object using a dynamic key.

Assuming another dynamic key is required, the following code accomplishes this:

const secondKey = "unicorns are";
myDynamicObject[secondKey] = "awesome sauce"

The console.log function will output the myDynamicObject object as shown:

{ 	"unicorns are": "awesome sauce",  DynamicKey: "some value" }

Tips and Best Practices

It's important to use dynamic keys appropriately. While they provide flexibility, overuse can lead to unclear and unpredictable code.


This tutorial has demonstrated two techniques for using dynamic keys with JavaScript objects, providing a foundation for more flexible and dynamic coding practices.

Additional Resources

To further your understanding of JavaScript objects, the following resources are recommended:

These resources should enhance your JavaScript proficiency and aid in producing efficient, dynamic code.

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