Benchmark: DateTimeFormat vs toLocaleString

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

/*your preparation JavaScript code goes here */
var options = {
  year: 'numeric', month: 'numeric', day: 'numeric',
  hour: 'numeric', minute: 'numeric', second: 'numeric',
  hour12: false,
  fractionalSecondDigits: 3,
}

Tests:

DateTimeFormat single
new Intl.DateTimeFormat('de-DE', options).format(new Date())
toLocaleString single
new Date().toLocaleString('de-DE', options)
DateTimeFormat 100
[...Array(100)].forEach((_, i) => new Intl.DateTimeFormat('de-DE', options).format(new Date()))
toLocaleString 100
[...Array(100)].forEach((_, i) => new Date().toLocaleString('de-DE', options))
DateTimeFormat 10000
[...Array(10000)].forEach((_, i) => new Intl.DateTimeFormat('de-DE', options).format(new Date()))
toLocaleString 10000
[...Array(10000)].forEach((_, i) => new Date().toLocaleString('de-DE', options))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
DateTimeFormat single
toLocaleString single
DateTimeFormat 100
toLocaleString 100
DateTimeFormat 10000
toLocaleString 10000

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
DateTimeFormat single	26269.6 Ops/sec
toLocaleString single	26848.9 Ops/sec
DateTimeFormat 100	264.6 Ops/sec
toLocaleString 100	269.0 Ops/sec
DateTimeFormat 10000	2.7 Ops/sec
toLocaleString 10000	2.7 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 months ago):

LLMs can make mistakes. Check important info.

The benchmark described in the provided JSON is designed to compare the performance of two different JavaScript approaches for formatting dates and times: `Intl.DateTimeFormat` and `toLocaleString`. Each approach leverages the locale-specific options defined in the `options` variable for consistent formatting and accurate comparisons.

### Options Compared

1. **`Intl.DateTimeFormat`**
   - **Usage**: `new Intl.DateTimeFormat('de-DE', options).format(new Date())`
   - **Pros**:
     - Provides a more comprehensive set of options with regard to locale-aware date and time formatting.
     - Efficient for repeated formatting, as it can instantiate the formatter once and use it for multiple dates, reusing internal resources.
   - **Cons**:
     - Overhead of creating an `Intl.DateTimeFormat` instance may have a slight performance hit if used for single formatting calls repeatedly.

2. **`toLocaleString`**
   - **Usage**: `new Date().toLocaleString('de-DE', options)`
   - **Pros**:
     - Easier to use for quick formatting of individual date instances.
   - **Cons**:
     - Potentially more performance-intensive for repeated formatting, as a new internal implementation may be invoked for each call.

### Comparison of Test Cases

- **Single Formatting**:
  - "DateTimeFormat single" vs. "toLocaleString single":
    - This part of the benchmark tests the performance of single calls to format the current date using both methods.
  
- **Batch Formatting (100 and 10,000 times)**:
  - Each subsequent test case "DateTimeFormat 100", "toLocaleString 100", "DateTimeFormat 10000", and "toLocaleString 10000":
    - These test bulk operations, checking how each method scales when formatting 100 and then 10,000 dates. The performance drop-off, if any, will be assessed as the number of executions increases.

### Benchmark Results Summary

- Based on the provided results, it appears that `toLocaleString` may have marginally better performance than `Intl.DateTimeFormat` for single instances, while both approaches see a significant drop in executions per second when moved to bulk formatting (from 100 to 10,000). This indicates increased efficiency trade-offs when moving from single to bulk operations, which is common in performance testing.

### Other Alternatives

1. **Custom Date Formatting Libraries**:
   - Libraries like **date-fns** or **moment.js** (though moment.js is now in maintenance mode) offer various formatting capabilities. These libraries can be more user-friendly but come with additional bundle size overhead.

2. **Native JavaScript Formatting**:
   - Custom functions using standard JavaScript date methods may provide flexibility for specific formats, but likely require additional implementation and could miss doing locale-sensitive formatting correctly.

3. **Temporal API**:
   - With the recent addition of the Temporal API (still being adopted), it offers modern date and time handling capabilities that could serve as alternatives to both approaches in JavaScript.

### Considerations

When deciding between `Intl.DateTimeFormat` and `toLocaleString`, you should consider the following:
- **Use Case**: Are you making one-off formats or processing large numbers of date formats?
- **Performance Needs**: If you're performance-critical, specifically in bulk operations, you may want to benchmark based on your exact use case.
- **Browser Compatibility**: The usage of the `Intl` object is generally well-supported, but always check compatibility if your application targets older browsers.

This benchmark provides valuable insights into how different JavaScript date formatting methods perform under varying loads, guiding developers in making informed decisions on date representation in their applications.

Related benchmarks:

DateTimeFormat vs toLocaleString (version: 1)

Comparing performance of: DateTimeFormat single vs toLocaleString single vs DateTimeFormat 100 vs toLocaleString 100 vs DateTimeFormat 10000 vs toLocaleString 10000

Created: 3 months ago by: Guest

Jump to the latest result

DateTimeFormat single

toLocaleString single

DateTimeFormat 100

toLocaleString 100

DateTimeFormat 10000

toLocaleString 10000

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 months ago):