Benchmark: Date constructor inputs (extended by input of pre-existing Date object)

Script Preparation code:

const preExistingDate = new Date('2024-11-16T13:17:21.8881');

Tests:

Today
new Date();
Zero date
new Date(0);
Unix Timestamp
new Date(1731792019);
Datetime
new Date('2024-11-16T13:17:21.888163-08:00');
Pre-existing Date object
new Date(preExistingDate)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Today
Zero date
Unix Timestamp
Datetime
Pre-existing Date object

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:136.0) Gecko/20100101 Firefox/136.0

Browser/OS: Firefox 136 on Windows

View result in a separate tab

Test name	Executions per second
Today	5167442.5 Ops/sec
Zero date	18410976.0 Ops/sec
Unix Timestamp	16556741.0 Ops/sec
Datetime	4392237.0 Ops/sec
Pre-existing Date object	14743464.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):

LLMs can make mistakes. Check important info.

The benchmark titled **"Date constructor inputs (extended by input of pre-existing Date object)"** evaluates the performance of the JavaScript `Date` constructor using different input scenarios. The benchmark was set up with a pre-existing `Date` object created with a specific date and time.

### Test Cases Overview:

1. **Today (`new Date();`)**: Tests the creation of a `Date` object representing the current date and time.
   
2. **Zero date (`new Date(0);`)**: Tests the creation of a `Date` object starting from the epoch time (January 1, 1970).
   
3. **Unix Timestamp (`new Date(1731792019);`)**: Tests creation of a `Date` object with a specified Unix timestamp.
   
4. **Datetime (`new Date('2024-11-16T13:17:21.888163-08:00');`)**: Tests creation of a `Date` object using a specific ISO 8601 formatted string.
   
5. **Pre-existing Date object (`new Date(preExistingDate);`)**: Tests creating a new `Date` object initialized with another `Date` object as input.

### Performance Results:
The benchmark results show the number of executions per second for each test case on a specific setup running Firefox 136 on Windows 10. Here are key insights based on the performance:

- **Best Performing Case**: The best performance was recorded with the **Zero date** test case, achieving approximately **18.4 million executions per second**. This is likely because initializing a `Date` with the value `0` is a straightforward operation that requires minimal computation.

- **Second Best Performing Case**: The **Unix Timestamp** case follows closely at about **16.6 million executions per second**. This likely involves calculations to interpret the timestamp into a date format, but it’s still a relatively simple operation.

- **Moderate Performance**: The **Pre-existing Date object** benchmark scored around **14.7 million executions per second**. In this case, the engine needs to handle an existing object, which incurs more overhead than simply using numeric values but is still efficient.

- **Lower Performance**: The **Today** case yielded around **5.2 million executions per second**, likely due to the complexity of obtaining the current time, which involves more internal checks and accesses.

- **Lowest Performance**: The **Datetime** string initialization resulted in around **4.4 million executions per second**. Parsing a date string in ISO format usually requires more resources and checks, leading to slower performance compared to the other methods.

### Comparison of Approaches:

- **Pros of Using Constants & Numeric Inputs**:
   - **Simplicity**: Numeric inputs (like `0`) lead to lower overhead due to straightforward calculations.
   - **Speed**: Cases like `new Date(0)` and `new Date(1731792019)` are faster because they require less parsing compared to strings.
   
- **Cons of Using Strings**:
   - **Parsing Overhead**: String inputs like ISO 8601 formatted dates must be parsed and validated, introducing latency.
   - **Consistency**: Variations in date format strings can lead to discrepancies based on locale settings and implementation.

- **Pre-existing Date Object Pros**:
   - **Flexibility**: This allows copying or cloning of a date instance, which can be useful in certain programming scenarios.
  
- **Pre-existing Date Object Cons**:
   - **Overhead**: Creating a new `Date` from another `Date` incurs additional overhead from referencing an object rather than using primitives.

### Alternative Considerations:
Apart from the `Date` constructor, other alternatives exist for date management in JavaScript:

- **Date Libraries**: Libraries such as **Moment.js**, **date-fns**, or **Luxon** provide more advanced date manipulation capabilities, including parsing, formatting, and operations on dates. However, more complex libraries may come with performance overhead and larger bundle sizes.
  
- **Modern API**: The **Temporal API** (currently a proposal) introduces a more powerful and versatile framework for date and time management, aiming to address the limitations of the existing `Date` object. However, it might not be feasible in all environments yet.

In conclusion, the benchmark highlights the performance implications of different ways of creating `Date` objects in JavaScript and serves as a guide for developers to make informed decisions regarding date handling based on performance needs in their applications.

Related benchmarks:

Date constructor inputs (extended by input of pre-existing Date object) (version: 1)

Comparing performance of: Today vs Zero date vs Unix Timestamp vs Datetime vs Pre-existing Date object

Created: one month ago by: Guest

Jump to the latest result

Today

Zero date

Unix Timestamp

Datetime

Pre-existing Date object

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):