Improve Readability with Numeric Separators in JavaScript

Improve Readability with Numeric Separators in JavaScript

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JavaScript's Numeric Separators provide an enhanced way to improve the readability of large numeric literals by allowing developers to use underscores as visual separators. This feature makes it easier to understand and maintain code that involves large numbers, particularly when dealing with currency, mathematical calculations, or data manipulation

For example, consider the following number: 1000000000. It takes a moment to discern if it represents a billion or a trillion. However, by utilizing numeric separators, we can rewrite the same number as: 1_000_000_000, which is much easier to interpret at first glance.

Numeric separators provide the following readability benefits:

  1. Enhanced Visual Clarity: By visually separating groups of digits, numeric separators make it easier to comprehend the magnitude of large numbers. This is especially helpful when working with numbers that have many digits, as the separators break them into more manageable chunks.

  2. Improved Code Maintenance: Readable code is easier to maintain, understand, and debug. By using numeric separators, developers can make their code more self-explanatory, reducing the time spent deciphering complex numerical values.

Usage Examples:

Let's look at a few examples to demonstrate how numeric separators can improve code readability:

  1. Monetary Values:

Instead of: const totalAmount = 1000000000;

We can use: const totalAmount = 1_000_000_000;

The second version provides a clear indication that the total amount is one billion, without requiring any mental calculations.

  1. File Sizes:

Instead of: const fileSize = 5000000000;

We can use: const fileSize = 5_000_000_000;

Here, the second version immediately conveys that the file size is 5 gigabytes, making it easier for developers to understand the context.

  1. Large IDs:

Instead of: const userId = 100000000000000000000;

We can use: const userId = 100_000_000_000_000_000_000;

The second version with numeric separators is much clearer and avoids confusion regarding the number of zeros present.

Browser Compatibility:

As with any new feature, it is essential to consider browser compatibility when utilizing numeric separators. At the time of writing, numeric separators are supported in most modern browsers, including Chrome, Firefox, Safari, and Edge. However, older browsers may not recognize this feature, so it is recommended to use transpilers or build systems to ensure backward compatibility if necessary.


JavaScript's introduction of numeric separators in ECMAScript 2021 provides developers with a valuable tool to improve code readability. By visually separating digits within numeric literals, developers can make their code more expressive and easier to understand, particularly when working with large numerical values. Utilizing numeric separators not only enhances visual clarity but also improves code maintenance and reduces the time spent interpreting complex numbers. As a developer, incorporating this feature into your JavaScript code can greatly enhance its readability and make it more accessible to yourself and others.