Benchmark: +new Date vs new Date().getTime() 100k

Tests:

+new Date
for(let i = 0; i < 100000;i++){ +new Date("2022-02-10T08:29:20.638Z"); }
new Date().getTime()
for(let i = 0; i < 100000;i++){ new Date("2022-02-10T08:29:20.638Z").getTime(); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.82 Safari/537.36

Browser/OS: Chrome 98 on Windows

View result in a separate tab

Test name	Executions per second
+new Date	19.8 Ops/sec
new Date().getTime()	23.3 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 JSON data and explain what is being tested, compared options, their pros and cons, and other considerations.

**Benchmark Definition**

The `Benchmark Definition` json represents a JavaScript microbenchmark that tests two approaches to get the current timestamp: using the `+new Date()` syntax versus `new Date().getTime()`. The benchmark aims to measure which approach is faster in terms of executions per second.

**Options Compared**

There are two options compared:

1. `+new Date()`: This method returns the number of milliseconds since the Unix Epoch (January 1, 1970, 00:00:00 UTC) as a floating-point number.
2. `new Date().getTime()`: This method returns the number of milliseconds since the Unix Epoch as an integer.

**Pros and Cons**

* `+new Date()`:
	+ Pros: Generally faster due to being a single operation, eliminating the overhead of creating a `Date` object and calling its methods.
	+ Cons: May not provide the most accurate result, especially if the timestamp needs to be precise. The `+` symbol is an arithmetic operator that returns the number of milliseconds since the Unix Epoch, which may lead to a loss of precision due to floating-point arithmetic issues.
* `new Date().getTime()`:
	+ Pros: Provides more accurate results, as it uses integer arithmetic and eliminates potential floating-point precision issues.
	+ Cons: Slower due to creating an additional `Date` object and calling its methods.

**Library and Special JS Feature**

Neither of the options requires a library or special JavaScript features. However, note that using `+new Date()` may not be supported in older browsers or environments that don't support arithmetic operators as property accessors (`obj.prop` instead of `obj.prop`).

**Other Considerations**

* The benchmark uses a fixed date string (`"2022-02-10T08:29:20.638Z"`), which is likely chosen for simplicity and to avoid issues with daylight saving time (DST) or other calendar-related complexities.
* The benchmark executes the test 100,000 times, providing a good estimate of the performance difference between the two approaches.

**Alternative Approaches**

Other alternatives to measure execution time in JavaScript include:

1. Using `Performance.now()`: This method returns the number of milliseconds since the browser's `PerformanceNavigation` event was fired (i.e., when the page finished loading).
2. Creating a high-performance timer using Web Workers or WebAssembly.
3. Utilizing specialized libraries like Benchmark.js or jsPerf for benchmarking.

These alternatives offer varying degrees of accuracy, performance, and complexity, depending on the specific use case.

Related benchmarks:

+new Date vs new Date().getTime() 100k (version: 0)

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

Created: 2 years ago by: Guest

Jump to the latest result

+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):