Benchmark: Date perf - MeasureThat.net

Tests:

+new Date()
+new Date()
Date.now()
Date.now()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
+new Date()
Date.now()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.102 Safari/537.36

Browser/OS: Chrome 85 on Windows

View result in a separate tab

Test name	Executions per second
+new Date()	2082928.2 Ops/sec
Date.now()	3505693.2 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the test cases and explain what's being tested, the different approaches, pros and cons of each approach, and other considerations.

**Test Cases:**

The test cases are designed to measure the performance difference between two ways of getting the current timestamp using the `Date` object in JavaScript:

1. `+new Date()`
2. `Date.now()`

These two methods are often used interchangeably, but they have some differences in terms of behavior and usage.

**Approaches:**

There are three approaches being compared in this test case:

A) Using `+new Date()`: This method creates a new `Date` object and returns its value as a timestamp. The "+" symbol before the function call is called "string concatenation" or "string addition." When used with `Date`, it's called "string parsing."

B) Using `Date.now()`: This method returns the timestamp of the current time in milliseconds since the Unix Epoch (January 1, 1970, 00:00:00 UTC).

**Pros and Cons:**

A) `+new Date()`:

Pros:

* Easy to use for developers who are familiar with string parsing.
* Can be used as a shorthand for getting the current timestamp.

Cons:

* Slower than `Date.now()`. This is because creating a new `Date` object involves some overhead, such as:
	+ Parsing the timestamp from a string (in this case, "current date").
	+ Creating a new object on the heap.
	+ Updating internal state (e.g., timezone offset).
* Can be less readable and maintainable than using `Date.now()`.

B) `Date.now()`: This method is generally faster because it:

Pros:

* Does not create a new `Date` object, avoiding unnecessary overhead.
* Is more concise and readable.

Cons:

* Less familiar to developers who are used to string parsing (as implied by the name "string concatenation").
* May be less intuitive for developers who are not aware of the performance difference between these two methods.

**Library Usage:**

There is no library usage in this test case. The `Date` object is a built-in JavaScript object, and both methods (`+new Date()` and `Date.now()`) use this object to get the current timestamp.

**Special JS Feature or Syntax:**

The "+" symbol before the function call (e.g., `"current date" + 0`) is an example of "string concatenation" or "string addition." This syntax is a shorthand way of converting a string to a number. In this case, it's used with `Date` objects.

**Other Considerations:**

* Performance differences between these two methods can have significant impacts on the performance of JavaScript applications that rely on timestamp calculations.
* Using `+new Date()` instead of `Date.now()` can lead to slower performance and more unexpected results in certain scenarios (e.g., when using timezone-aware date formatting).

**Alternatives:**

If you need to measure the performance difference between different ways of getting the current timestamp, there are other alternatives:

1. Use a benchmarking library like Benchmark.js or Fast benchmarks.
2. Create your own benchmarking script using `Benchmark` or similar libraries.

These alternatives can provide more control and flexibility in setting up and running your benchmarks, as well as handling edge cases and errors.

Related benchmarks:

Date perf (version: 0)

Comparing performance of: +new Date() vs Date.now()

Created: 4 years ago by: Guest

Jump to the latest result

+new Date()

Date.now()

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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