Benchmark: Date.now() vs new Date() vs performance.now()

Script Preparation code:

var timestamp = null;

Tests:

Date.now()
timestamp = Date.now();
new Date();
timestamp = new Date();
performance.now()
timestamp = performance.now()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Date.now()
new Date();
performance.now()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:147.0) Gecko/20100101 Firefox/147.0

Browser/OS: Firefox 147 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Date.now()	28529338.0 Ops/sec
new Date();	24682098.0 Ops/sec
performance.now()	11619598.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in this benchmark.

**What is being tested?**

The benchmark is designed to compare the performance of three different methods to get the current time:

1. `Date.now()`
2. `new Date()`
3. `performance.now()`

These methods are used to measure the passage of time, but they have different characteristics that affect their performance.

**Options being compared**

The options being compared are:

* `Date.now()`: This method returns the number of milliseconds since the Unix Epoch (January 1, 1970, 00:00:00 UTC). It's a simple and straightforward way to get the current time.
* `new Date()`: This method creates a new `Date` object representing the current date and time. While it may seem similar to `Date.now()`, creating a new `Date` object can be more expensive due to object creation overhead.
* `performance.now()`: This method returns the number of milliseconds since the performance counter was started. It's designed specifically for measuring elapsed time in high-performance applications.

**Pros and Cons**

Here are some pros and cons of each approach:

* `Date.now()`:
	+ Pros: Simple, fast, and widely supported.
	+ Cons: May not be suitable for very large intervals (e.g., measuring the passage of hours or days), as it uses a fixed epoch value that may drift over time.
* `new Date()`:
	+ Pros: Can provide more precision than `Date.now()`, as it creates a new object with a specific timestamp.
	+ Cons: More expensive due to object creation overhead, and may not be suitable for high-performance applications where speed is critical.
* `performance.now()`:
	+ Pros: Specifically designed for measuring elapsed time in high-performance applications, providing the best possible accuracy and speed.
	+ Cons: May not be supported in older browsers or environments that don't have a performance counter.

**Library**

None of these methods rely on any external libraries. They are all built-in JavaScript functions.

**Special JS feature or syntax**

There's no special JavaScript feature or syntax being used here, just standard JavaScript function calls.

**Other alternatives**

If you need more precise timing or want to measure time intervals in a specific unit (e.g., milliseconds, seconds), you may consider using other libraries like `ms` or `moment.js`. However, for simple cases where you just need to measure the passage of time, these built-in methods should be sufficient.

Keep in mind that while these methods are suitable for most use cases, there may be specific requirements for high-performance applications or situations where accuracy is critical. In such cases, more specialized libraries or frameworks might be necessary.

Related benchmarks:

Date.now() vs new Date() vs performance.now() (version: 0)

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

Created: 5 years ago by: Registered User

Jump to the latest result

Date.now()

new Date();

performance.now()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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