Benchmark: Intl.NumberFormat vs toLocaleString vs Custom Formatter vs Pre-created Intl formatter

Script Preparation code:

function formatUSD(a) {
	const [str, fraction] = String(a).split('.');
	return '$' + str.split('').reverse().join('').match(/\d{1,3}/g).join().split('').reverse().join('') + '.' + fraction;
}

var formatIntlUSD = new Intl.NumberFormat("en-US", { style: 'currency', currency: 'USD' });

Tests:

Intl.NumberFormat
var a = new Intl.NumberFormat("en-US", { style: 'currency', currency: 'USD' }).format(10000.56);
toLocalString
var a = (10000.56).toLocaleString("en-US", { style: 'currency', currency: 'USD' });
Custom Formatter
var a = formatUSD(10000.56);
Pre-created Intl formatter
var a = formatIntlUSD.format(10000.56);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Intl.NumberFormat
toLocalString
Custom Formatter
Pre-created Intl formatter

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its test cases.

**Benchmark Overview**

The benchmark measures the performance of different approaches for formatting currency values. The options being compared are:

1. `Intl.NumberFormat`: uses the built-in Intl API to format numbers as currencies.
2. `toLocaleString` with a currency style option: uses the `toLocaleString` method to format numbers, specifying a currency style.
3. A custom formatter function: a user-defined function that formats numbers as currencies.
4. A pre-created Intl formatter instance: an instance of `Intl.NumberFormat` specifically created for formatting USD values.

**Pros and Cons of each approach**

1. **Intl.NumberFormat**:
	* Pros: widely supported, easy to use, provides a standardized way of formatting currency values.
	* Cons: may have performance issues in older browsers or with large datasets.
2. **toLocaleString** with currency style option:
	* Pros: simpler to implement than Intl API, works well for small datasets.
	* Cons: not as robust as Intl API, limited options for customizing formatting.
3. **Custom Formatter**:
	* Pros: provides full control over formatting, can be optimized for performance.
	* Cons: requires more development effort, may have compatibility issues with older browsers or other systems.
4. **Pre-created Intl formatter instance**:
	* Pros: optimized for formatting USD values, easy to use.
	* Cons: limited options for customizing formatting, may require additional setup.

**Library and purpose**

The Intl API is a built-in JavaScript library that provides functions for working with internationalization and localization tasks. In this benchmark, it's used for formatting numbers as currencies using `Intl.NumberFormat`.

**Special JS feature or syntax**

None mentioned in the provided code snippet.

**Alternative approaches**

Other approaches to formatting currency values might include:

1. Using a third-party library like moment.js or date-fns.
2. Implementing a custom formatter function using regular expressions and string manipulation.
3. Using a template engine like Handlebars or Mustache to generate formatted strings.

In general, the choice of approach depends on the specific requirements of your project, including performance, complexity, and compatibility with older browsers or systems.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36

Browser/OS: Chrome 108 on Windows

View result in a separate tab

Test name	Executions per second
Intl.NumberFormat	21490.0 Ops/sec
toLocalString	23346.4 Ops/sec
Custom Formatter	546538.0 Ops/sec
Pre-created Intl formatter	1024257.2 Ops/sec

Related benchmarks:

Intl.NumberFormat vs toLocaleString vs Custom Formatter vs Pre-created Intl formatter (version: 0)

Comparing performance of: Intl.NumberFormat vs toLocalString vs Custom Formatter vs Pre-created Intl formatter

Created: one year ago by: Registered User

Jump to the latest result

Intl.NumberFormat

toLocalString

Custom Formatter

Pre-created Intl formatter

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):