# 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.

Source: https://curiouslychase.com/engineering/interpolate-a-javascript-variable-for-an-object-key/

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.

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

# Objective
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:

```typescript
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.

```typescript
const someKey = "DynamicKey"
```

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

```typescript
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:

```typescript
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:

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

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

```json
{ 	"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.

# Summary
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:

- [MDN Web Docs: Working with Objects](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Working_with_Objects)
- [W3Schools: JavaScript Objects](https://www.w3schools.com/js/js_objects.asp)

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