How to Use a Variable as a Property Name in JavaScript Objects

Learn how to dynamically assign a variable value as a property name in JavaScript objects using square brackets.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to use the value of a variable as a property of an object?

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Use a Variable as a Property Name in JavaScript Objects

In the world of JavaScript, developers often need to create objects that can store information in a flexible way. However, one common issue that many encounter is trying to use variable values as property names. If you've ever tried to set a property name using a variable and faced confusion, you're not alone. Let's break down the problem and discover the straightforward solution.

The Problem: Using a Variable as a Property Name

Consider the following scenario: you have a variable that holds a string value, and you want to use that value as a property name in an object. Here's a code example that illustrates the confusion:

[[See Video to Reveal this Text or Code Snippet]]

In this example, instead of creating a property named Carros, the property is mistakenly named categoria. This happens because JavaScript interprets the categoria in the object definition as a string literal instead of the value of the variable.

Attempting to Use Template Literals

When the developer attempted to correct this by using template literals:

[[See Video to Reveal this Text or Code Snippet]]

This results in a template string error. The frustration is understandable, but fear not—there is a simple solution to this issue!

The Solution: Use Square Brackets

The solution to dynamically assign a variable’s value as a property name is to utilize square brackets around the variable name when defining the object. This allows JavaScript to recognize the value of the variable instead of treating it as a literal string.

Updated Code Example

Below is a revised version of the original attempt that correctly assigns the variable value as a property name:

[[See Video to Reveal this Text or Code Snippet]]

How It Works

Square Brackets: The key change here is the use of square brackets [categoria]. This tells JavaScript to evaluate the variable categoria and use its value as the property name instead of the string "categoria".

Spread Operator: The spread operator (...) is used to maintain any other properties already present in the categorias object.

Output of the Correct Code

When you run the corrected code, the output will be:

[[See Video to Reveal this Text or Code Snippet]]

This output confirms that the property name has been successfully set as Carros, as intended.

Conclusion

Using a variable as a property name in JavaScript objects can lead to confusion if not done correctly. By following the simple practice of using square brackets, you can dynamically assign values to property names and avoid the pitfalls of string literals. Now, you can enhance your JavaScript coding skills and create more dynamic and efficient object structures. Happy coding!