Benchmark: Intl.NumberFormat vs RegExp

Script Preparation code:

const formatNumberToFloat = new Intl.NumberFormat('ru-RU', {
    style: 'decimal',
    maximumFractionDigits: 2,
    minimumFractionDigits: 2,
})

Tests:

Intl.NumberFormat
const formatNumberToFloat = new Intl.NumberFormat('ru-RU', { style: 'decimal', maximumFractionDigits: 2, minimumFractionDigits: 2, }) var a = formatNumberToFloat.format("10000.999999");
toLocalString
var a = (Math.round( "10000.999999" * 100 + Number.EPSILON ) / 100).toFixed(2); var b = a.replace(/(\d)(?=(\d{3})+(?!\d))/g, '$1 ')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Intl.NumberFormat
toLocalString

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its components.

**Overview**

The benchmark compares two approaches to formatting numbers: using the `Intl.NumberFormat` API and regular expressions (RegExp). The goal is to determine which approach is faster for this specific use case.

** Intl.NumberFormat API**

The `Intl.NumberFormat` API is a built-in JavaScript API that provides support for formatting numbers according to the rules of different cultures. In this benchmark, we're using it to format a Russian decimal number with two fractional digits.

**Script Preparation Code**

The script preparation code creates an instance of `Intl.NumberFormat` with specific settings:
```javascript
const formatNumberToFloat = new Intl.NumberFormat('ru-RU', {
  style: 'decimal',
  maximumFractionDigits: 2,
  minimumFractionDigits: 2,
});
```
This code sets the formatting style to decimal, and limits the number of fractional digits to 2.

**Test Case**

The test case consists of two parts:

1. The first part defines a variable `a` using the `formatNumberToFloat` instance:
```javascript
var a = formatNumberToFloat.format("10000.999999");
```
This code formats the string "10000.999999" according to the Russian decimal rules, resulting in a formatted number.

2. The second part defines another variable `a` using regular expressions:
```javascript
var b = (Math.round("10000.999999" * 100 + Number.EPSILON) / 100).toFixed(2);
var c = b.replace(/(\\d)(?=(\\d{3})+(?!\\d))/g, '$1 ');
```
This code uses regular expressions to extract every third digit from the number and append a space after each one.

**Pros and Cons**

Using `Intl.NumberFormat` has several advantages:

* It's a built-in API, so it's likely to be fast and efficient.
* It provides accurate formatting according to specific cultural rules.
* It eliminates the need for manual implementation of decimal rules.

However, using `Intl.NumberFormat` also has some limitations:

* It may not work correctly in older browsers or environments that don't support this API.
* The performance can vary depending on the browser and its locale settings.

On the other hand, regular expressions (RegExp) have the following advantages:

* They are widely supported across most browsers and environments.
* They provide a high degree of control over formatting.
* However, they require manual implementation of decimal rules, which can be error-prone and slow.

However, using RegExp also has some disadvantages:

* It requires more code and is potentially slower than `Intl.NumberFormat`.
* The performance can vary depending on the browser and its locale settings.

**Other Considerations**

Another consideration is that this benchmark only measures the execution time of formatting a single number. In real-world scenarios, you may need to format multiple numbers, which could impact the overall performance.

Additionally, if you're using `Intl.NumberFormat`, make sure to handle errors and exceptions properly, as it can throw errors for invalid input or unsupported locales.

**Alternatives**

If you don't want to use `Intl.NumberFormat`, alternative approaches include:

* Using a third-party library like moment.js or date-fns.
* Implementing decimal rules manually using regular expressions or mathematical calculations.
* Using a different formatting API, such as the one provided by the Google Closure Library.

However, these alternatives may have their own trade-offs in terms of performance, accuracy, and maintainability.

Latest run results:

Run details: (Test run date: 11 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:121.0) Gecko/20100101 Firefox/121.0

Browser/OS: Firefox 121 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Intl.NumberFormat	36439.8 Ops/sec
toLocalString	3229272.0 Ops/sec

Related benchmarks:

Intl.NumberFormat vs RegExp (version: 0)

Comparing performance of: Intl.NumberFormat vs toLocalString

Created: 3 years ago by: Guest

Jump to the latest result

Intl.NumberFormat

toLocalString

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):