Benchmark: new Date from UNIX timestamp (ms) vs new Date from ISO string

Tests:

new Date
new Date(1576610077000);
Date.parse
Date.parse('2019-07-31T13:03:00.000Z');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Date
Date.parse

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its test cases to understand what is being tested.

**What is being measured?**

The benchmark is measuring the performance of two different approaches to create a `Date` object in JavaScript:

1. **new Date(timestamp)**: This approach takes a Unix timestamp (in milliseconds) as an argument and creates a new `Date` object from it.
2. **Date.parse(isoString)**: This approach takes an ISO string (e.g., "2019-07-31T13:03:00.000Z") as an argument and parses it into a `Date` object.

**Options compared**

Two options are being compared:

* **new Date(timestamp)**
* **Date.parse(isoString)**

The pros and cons of these approaches are:

* **new Date(timestamp)**:
	+ Pros:
		- Simple and straightforward way to create a `Date` object.
		- Fast execution, as it directly converts the timestamp to milliseconds.
	+ Cons:
		- May not be accurate for large timestamps or edge cases (e.g., timestamp overflow).
* **Date.parse(isoString)**:
	+ Pros:
		- More flexible and forgiving than `new Date(timestamp)`, as it can handle various ISO string formats and edge cases.
	+ Cons:
		- Slower execution, as it involves parsing the ISO string.

**Library usage**

In this benchmark, no specific JavaScript library is used beyond the built-in `Date` object and `String.prototype.localeCompare()` (not explicitly mentioned in the provided code). However, it's worth noting that some browsers might have additional libraries or extensions available for date-related operations.

**Special JS feature or syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark. It only focuses on comparing two simple approaches to create a `Date` object.

**Other alternatives**

If you want to compare other approaches to creating a `Date` object, some possible alternatives could be:

* Using the `Intl.DateTimeFormat` API
* Utilizing the `moment.js` library (not part of the benchmark)
* Implementing a custom date parsing function

Keep in mind that these alternatives might not be directly comparable to the original two approaches being tested in this benchmark.

Let me know if you have any further questions!

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0

Browser/OS: Firefox 89 on Windows 7

View result in a separate tab

Test name	Executions per second
new Date	13549160.0 Ops/sec
Date.parse	6410594.0 Ops/sec

Related benchmarks:

new Date from UNIX timestamp (ms) vs new Date from ISO string (version: 0)

Comparing performance of: new Date vs Date.parse

Created: 3 years ago by: Guest

Jump to the latest result

new Date

Date.parse

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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