Benchmark: cached Number.toLocaleString vs Intl.NumberFormat vs Regex

Script Preparation code:

const formatter = new Intl.NumberFormat(undefined, {
    style: 'currency',
    currency: 'RUB',
});

Tests:

Intl.NumberFormat
const currencyPlayNumber = 1; const translatedString = formatter.format(currencyPlayNumber);
Number.toLocaleString
const currencyPlayNumber = 1; const translatedString = currencyPlayNumber.toLocaleString(undefined, { style: 'currency', currency: 'RUB', })
Regex
const currencyPlayNumber = 1; const translatedString = `${currencyPlayNumber}`.replace(/\B(?=(\d{3})+(?!\d))/g, ',');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Intl.NumberFormat
Number.toLocaleString
Regex

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 days ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Linux

View result in a separate tab

Test name	Executions per second
Intl.NumberFormat	3984434.8 Ops/sec
Number.toLocaleString	59979.1 Ops/sec
Regex	34547992.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 8 days ago):

LLMs can make mistakes. Check important info.

The benchmark you provided evaluates the performance of three different methods for formatting numbers as currency in JavaScript. These methods are:

1. **Intl.NumberFormat**
2. **Number.toLocaleString**
3. **Regex-based formatting**

### Options Compared

1. **Intl.NumberFormat**
   - **Description**: The `Intl.NumberFormat` API is part of the ECMAScript Internationalization API. It provides a way to format numbers according to locale-specific conventions. In this benchmark, it is configured to format currency specifically in Russian Rubles (RUB).
   - **Pros**:
     - Handles various locale-specific formatting options automatically.
     - More readable and maintainable code due to clear intent.
     - Less error-prone as it manages complexities of number formatting.
   - **Cons**:
     - Potentially slower than simpler string manipulation methods due to its comprehensive features.
     - It’s a newer API, so may not be supported in very old JavaScript environments.

2. **Number.toLocaleString**
   - **Description**: The `toLocaleString()` method converts a number to a string, using locale-based formatting. Similar to `Intl.NumberFormat`, it can take options for different styles, including currency.
   - **Pros**:
     - Simple and straightforward for currency formatting.
     - Easy to read and understand.
     - Well-supported across modern browsers.
   - **Cons**:
     - Performance could be less optimal compared to other methods, especially in tight loops where it may be invoked repeatedly.
     - Lacks fine-tuning options that might be found in more specific libraries or APIs.

3. **Regex-based formatting**
   - **Description**: This approach uses a regular expression to manually format a number into a string with commas as thousand separators.
   - **Pros**:
     - Fast execution speed, as indicated by benchmark results.
     - Simplicity in environments where only basic string manipulation is available.
   - **Cons**:
     - Less readable and maintainable due to the complexity of regular expressions.
     - Doesn’t handle locale-specific formatting or currency symbols, making it less versatile.
     - Potential for errors in more complex formatting scenarios.

### Benchmark Results

From the provided benchmark results, we see that:
- **Regex** achieved the highest execution speed with approximately 34.5 million executions per second.
- **Intl.NumberFormat** performed at about 3.98 million executions per second.
- **Number.toLocaleString** was significantly slower at approximately 60,000 executions per second.

### Other Alternatives and Considerations

- **Libraries**: Instead of using native JavaScript methods, developers might consider using libraries specifically designed for internationalization and number formatting, such as **Numeral.js** or **accounting.js**. These libraries can offer additional features and would come with varying performance characteristics depending on their implementation.
  
- **Performance**: For applications where performance is critical (like games or high-frequency data display), the regex method may be preferable despite its complexity. However, for applications where accuracy and internationalization are important—such as e-commerce—`Intl.NumberFormat` or `Number.toLocaleString` would be better suited.

- **Polyfills**: If targeting older browsers or environments that lack support for `Intl.NumberFormat`, polyfills can be used, but they may add overhead to the application.

Each approach has its own strengths and weaknesses, and the choice of which to use should be determined by the specific needs of the application, developer preferences, and performance requirements.

Related benchmarks:

cached Number.toLocaleString vs Intl.NumberFormat vs Regex (version: 1)

Comparing performance of: Intl.NumberFormat vs Number.toLocaleString vs Regex

Created: 8 days ago by: Guest

Jump to the latest result

Intl.NumberFormat

Number.toLocaleString

Regex

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 8 days ago):