Benchmark: Date.now() vs + new Date() vs new Date.getTime()

Tests:

Date.now()
const timestamp = Date.now();
+ new Date();
const timestamp = + new Date();
new Date().getTime();
const timestamp = new Date().getTime();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.72 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
Date.now()	2851394.0 Ops/sec
+ new Date();	1590080.9 Ops/sec
new Date().getTime();	2163533.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark definition is a JSON object that describes the test case:

```
{
  "Name": "Date.now() vs + new Date() vs new Date.getTime()"
}
```

This benchmark is comparing three different ways to get the current timestamp in JavaScript:

1. `Date.now()`: This method returns the number of milliseconds since the Unix Epoch (January 1, 1970, 00:00:00 UTC).
2. `+ new Date()`: This method uses the `new Date()` constructor and then adds the `NaN` (Not a Number) value to the result. The `NaN` value is essentially ignored when added to any number.
3. `new Date().getTime()`: This method returns the number of milliseconds since the Unix Epoch, similar to `Date.now()`.

**Options Compared**

The benchmark is comparing these three options:

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

The pros and cons of each approach are:

* `Date.now()`: This method is simple and efficient, but it may not be the most accurate due to potential timing issues in the JavaScript engine.
* `+ new Date()`: This method is less intuitive and less efficient than `Date.now()`, as the `NaN` value is essentially ignored. However, it's still a valid way to get the current timestamp.
* `new Date().getTime()`: This method is similar to `Date.now()` but may be slightly slower due to the additional overhead of calling the `getTime()` method.

**Library and Special Features**

There are no libraries used in this benchmark, but it does use a special JavaScript feature:

* The `+` operator is used as a unary plus operator with `new Date()`, which returns the timestamp. This syntax is specific to JavaScript and allows for implicit conversion of the result to an integer.

**Other Considerations**

When testing these three options, we should also consider factors such as:

* Performance: How fast are each option in terms of executing the benchmark?
* Accuracy: Are the results accurate enough for the intended use case?
* Code readability: Which option is more readable and maintainable?

**Alternatives**

If you were to write a similar benchmark, you could explore other options, such as:

* Using `performance.now()` (available in modern browsers): This method returns the high-resolution timestamp in milliseconds.
* Using a third-party library like `moment-timezone` or `luxon`: These libraries provide more robust and accurate date and time handling functions.

Keep in mind that each option has its pros and cons, and the best choice depends on the specific requirements of your project.

Related benchmarks:

Date.now() vs + new Date() vs new Date.getTime() (version: 0)

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

Created: 3 years ago by: Guest

Jump to the latest result

Date.now()

+ new Date();

new Date().getTime();

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):