Benchmark: new Intl.DateTimeFormat vs no new Intl.DateTimeFormat

Script Preparation code:

const TWO_DIGIT = '2-digit';

var options = {
      month: TWO_DIGIT,
      year: 'numeric',
      day: TWO_DIGIT,
      hour: TWO_DIGIT,
      hour12: false,
      minute: TWO_DIGIT,
      second: TWO_DIGIT,
    }

var cached = new Intl.DateTimeFormat('en-US', options);

Tests:

new Intl.DateTimeFormat.format()
new Intl.DateTimeFormat('en-US', options).format(new Date());
Intl.DateTimeFormat.format()
Intl.DateTimeFormat('en-US', options).format(new Date());
new Intl.DateTimeFormat.formatToParts
new Intl.DateTimeFormat('en-US', options).formatToParts(new Date());
Intl.DateTimeFormat.formatToParts
Intl.DateTimeFormat('en-US', options).formatToParts(new Date());

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Intl.DateTimeFormat.format()
Intl.DateTimeFormat.format()
new Intl.DateTimeFormat.formatToParts
Intl.DateTimeFormat.formatToParts

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: yesterday)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser/OS: Chrome 135 on Windows

View result in a separate tab

Test name	Executions per second
new Intl.DateTimeFormat.format()	17907.7 Ops/sec
Intl.DateTimeFormat.format()	17730.5 Ops/sec
new Intl.DateTimeFormat.formatToParts	17823.8 Ops/sec
Intl.DateTimeFormat.formatToParts	17882.4 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 days ago):

LLMs can make mistakes. Check important info.

The benchmark provided measures the performance difference between using `new Intl.DateTimeFormat` and calling `Intl.DateTimeFormat` directly, specifically focusing on formatting dates and extracting date components through two different methods: `format()` and `formatToParts()`.

### Options Compared
1. **Instantiation vs. Static Method Calls**:
   - **`new Intl.DateTimeFormat(...)`**: This approach instantiates a new object for formatting. Every time you call `new Intl.DateTimeFormat`, you create a new instance configured with the specific options provided.
   - **`Intl.DateTimeFormat(...)`**: In this case, although the code is technically valid JavaScript, it doesn't use `new` to instantiate a new object. Instead, it calls the `Intl.DateTimeFormat` without creating a specific instance, which can lead to subtle and platform-dependent behavior.

2. **Method Variants**:
   - **`format(date)`**: This method accepts a date object and returns a string based on the specified formatting options.
   - **`formatToParts(date)`**: This method also takes a date object but returns an array of objects representing the individual parts of the formatted date (like day, month, and year), which can be useful for more customized output.

### Pros and Cons
#### Pros of Using `new Intl.DateTimeFormat`:
- **Caching**: By creating a single instance of `Intl.DateTimeFormat` and re-using it across multiple calls to format dates, you leverage optimizations that can lead to better performance. The internal initialization is only done once.
- **Consistency**: This method ensures that all formatted outputs during the instance's lifetime will follow the same configuration.

#### Cons of Using `new Intl.DateTimeFormat`:
- **Memory Usage**: Each instantiation of a new object requires memory allocation, which can become expensive if done excessively in loops or high-frequency calls.

#### Pros of Using `Intl.DateTimeFormat` Directly**:
- **Simplicity**: In scenarios where formatting is done infrequently or as one-off cases, using the static method might seem simpler to implement.
- **No Memory Overhead**: Not creating an instance each time can reduce the overhead associated with object instantiation.

#### Cons of Using `Intl.DateTimeFormat` Directly**:
- **Performance**: This approach could be slower because it requires additional internal calculations and setups with each call.
- **Potential for Error**: Calling methods without the `new` keyword might not behave correctly due to variations in implementation and isn't a common or recommended practice.

### Libraries and Features
**`Intl.DateTimeFormat`**:
- **Purpose**: This is a built-in part of the ECMAScript Internationalization API (Intl), which provides language-sensitive string comparison, number formatting, and date and time formatting.
- **Use Case**: It's particularly useful in applications where displaying dates and times needs to respect the locale-specific formats, improving user experience across different geographical regions.

### Considerations
In performance-critical applications, particularly those dealing with dates in loops (like in reporting dashboards or during heavy data processing), caching instances of `Intl.DateTimeFormat` should be preferred. Developers should weigh factors like frequency of calls and potential memory limitations when deciding between instantiation methods.

### Alternatives
1. **Date Libraries**: Libraries like **Moment.js** or **date-fns** offer extensive date manipulation features. They may come with additional functionality (like time zone handling) that could be beneficial, but at the cost of increased size and potentially slower performance compared to built-in solutions, especially in scenarios where only formatting is needed.

2. **Native JavaScript Date Functions**: While not as robust as `Intl.DateTimeFormat`, some developers may opt for using native date functions combined with string manipulations for simple date formatting requirements.

3. **Caching Mechanisms**: Developers could implement their own caching layer if opting for heavy use of date formats where maximum performance is essential.

This benchmark serves as a useful guide for understanding performance considerations when working with internationalization in JavaScript, particularly for date formatting. Understanding the trade-offs will enable engineers to make informed decisions based on the specific use cases they are working on.

Related benchmarks:

new Intl.DateTimeFormat vs no new Intl.DateTimeFormat (version: 1)

measure the perf impact of caching calls to new Intl.DateTimeFormat

Comparing performance of: new Intl.DateTimeFormat.format() vs Intl.DateTimeFormat.format() vs new Intl.DateTimeFormat.formatToParts vs Intl.DateTimeFormat.formatToParts

Created: 6 days ago by: Guest

Jump to the latest result

new Intl.DateTimeFormat.format()

Intl.DateTimeFormat.format()

new Intl.DateTimeFormat.formatToParts

Intl.DateTimeFormat.formatToParts

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 days ago):