Benchmark: Intl.DateTimeFormat (optimized) vs new Date().toLocaleDateString()

Script Preparation code:

var options = {
  year: 'numeric', month: 'numeric', day: 'numeric',
  hour: 'numeric', minute: 'numeric', second: 'numeric',
  hour12: false,
  fractionalSecondDigits: 3,
}
var intlFormat = new Intl.DateTimeFormat('en-US', options);

Tests:

new Date()
(new Date()).toISOString().trim().replace('T', ' ').replace('Z', '')
Intl.DateTimeFormat()
intlFormat.format(new Date())
Date().toLocaleString()
new Date().toLocaleString("en-US", options)
JavaScript Date Time format
let date_time = new Date() let formatted_date = date_time.getFullYear() + "-" + (date_time.getMonth() + 1) + "-" + date_time.getDate() + " " + date_time.getHours() + ":" + date_time.getMinutes() + ":" + date_time.getSeconds() + "." + date_time.getMilliseconds()
JavaScript Date Time format using Template Strings.
let date_time = new Date() let formatted_date = `${date_time.getFullYear()}-${date_time.getMonth() + 1}-${date_time.getDate()} ${date_time.getHours()}:${date_time.getMinutes()}:${date_time.getSeconds()}.${date_time.getMilliseconds()}`

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Date()
Intl.DateTimeFormat()
Date().toLocaleString()
JavaScript Date Time format
JavaScript Date Time format using Template Strings.

Fastest: N/A

Slowest: N/A

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/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
new Date()	1427766.8 Ops/sec
Intl.DateTimeFormat()	740363.4 Ops/sec
Date().toLocaleString()	21434.3 Ops/sec
JavaScript Date Time format	1503405.4 Ops/sec
JavaScript Date Time format using Template Strings.	6510590.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the benchmark.

**What is tested on the provided JSON?**

The benchmark compares the performance of three different approaches to format dates in JavaScript:

1. **Intl.DateTimeFormat()**: A built-in JavaScript API that provides internationalized formatting for dates and numbers.
2. **new Date().toLocaleString()`**: A method that formats a date object according to the locale's conventions.
3. **Custom string concatenation**: Two variants of this approach, using either template literals or traditional string concatenation.

**Options compared**

The options being compared are:

* Format style (year-month-day vs year-month-day hh:mm:ss)
* Time zone representation (12-hour clock vs 24-hour clock)
* Fractional second digits

**Pros and Cons of each approach**

1. **Intl.DateTimeFormat()**:
	* Pros: Fast, efficient, and provides internationalized formatting.
	* Cons: May not work in older browsers or environments that don't support the Intl API.
2. **new Date().toLocaleString()`:
	* Pros: Widely supported, easy to use, and works well for simple date formatting.
	* Cons: Can be slower than Intl.DateTimeFormat() due to locale-specific calculations.
3. **Custom string concatenation**:
	* Pros: Control over formatting options, can be faster than using the built-in methods.
	* Cons: More error-prone, harder to maintain, and may not work as expected in all cases.

**Library usage**

The Intl.DateTimeFormat() function uses the Internationalization API (Intl), which is a part of the ECMAScript standard. The purpose of this library is to provide internationalized formatting for dates and numbers, making it easier to handle cultural differences.

**Special JS features or syntax**

None mentioned explicitly in the provided benchmark definition. However, it's worth noting that the Intl.DateTimeFormat() function uses Unicode characters (e.g., ℰ) for its display format, which can be affected by the locale settings.

**Other alternatives**

If you were to consider alternative approaches, you might also look into:

* Using a third-party library like Moment.js or Luxon, which provide more extensive date formatting capabilities.
* Utilizing a templating engine like Handlebars or Mustache for custom string concatenation.
* Exploring other methods, such as using regular expressions or JSON-based string formatting.

Keep in mind that each approach has its trade-offs, and the choice ultimately depends on your specific requirements, performance needs, and target audience.

Related benchmarks:

Intl.DateTimeFormat (optimized) vs new Date().toLocaleDateString() (version: 0)

Comparing performance of: new Date() vs Intl.DateTimeFormat() vs Date().toLocaleString() vs JavaScript Date Time format vs JavaScript Date Time format using Template Strings.

Created: 4 years ago by: Guest

Jump to the latest result

new Date()

Intl.DateTimeFormat()

Date().toLocaleString()

JavaScript Date Time format

JavaScript Date Time format using Template Strings.

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):