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

Script Preparation code:

var now = Date.now

Tests:

Date.now()
var x = Date.now()
now()
var x = now()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36

Browser/OS: Chrome 116 on Windows

View result in a separate tab

Test name	Executions per second
Date.now()	6329166.5 Ops/sec
now()	8543692.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the provided JSON benchmark definition and test cases.

**What is being tested?**

The main goal of this benchmark is to compare the performance of two approaches:

1. Assigning `Date.now()` to a variable (`var x = Date.now()`).
2. Calling `Date.now()` directly without assigning it to a variable (`now()`).

In other words, the test is comparing the cost of accessing and reusing the current timestamp value versus calling the `Date.now()` method every time.

**Options being compared**

Two options are being compared:

1. **Assignment**: Assigning `Date.now()` to a variable (`var x = Date.now()`). This approach involves creating a new variable and storing the result in memory.
2. **Direct call**: Calling `Date.now()` directly without assigning it to a variable (`now()`). This approach involves simply invoking the method without creating any additional memory allocation.

**Pros and Cons of each approach**

1. **Assignment (var x = Date.now())**
	* Pros:
		+ Can be useful when you need to reuse the result, e.g., in calculations or comparisons.
		+ May be more convenient for developers who prefer a variable to store the result.
	* Cons:
		+ Creates additional memory allocation, which can incur overhead due to garbage collection.
		+ May lead to slower performance due to the initial assignment step.
2. **Direct call (now())**
	* Pros:
		+ Avoids the overhead of creating a new variable and storing the result in memory.
		+ Can be more efficient since it only involves a single method invocation.
	* Cons:
		+ Requires calling the `Date.now()` method again on each execution, which may be slower if the method is expensive or has side effects.

**Special considerations**

The test case uses the `now()` function, which is likely an alias for `Date.now()`. This suggests that the benchmark author wants to explore the performance of assigning a shorter identifier (`now`) to the same value as using the longer identifier (`Date.now()`).

There are no special JavaScript features or syntax used in this benchmark.

**Other alternatives**

Alternative approaches could include:

1. **Using a different timestamp source**: Instead of relying on `Date.now()`, the benchmark could use other sources, such as the high-resolution timer (e.g., `performance.now()` in modern browsers).
2. **Adding more variables or computations**: Additional variables or calculations could be added to the assignment approach to make it more comparable to the direct call.
3. **Using a different JavaScript version or platform**: Benchmarking on different JavaScript versions, platforms, or environments could help identify any platform-specific optimizations or performance differences.

Overall, this benchmark is designed to explore the performance trade-offs between assigning a value and calling a method directly, highlighting the importance of optimization in JavaScript development.

Related benchmarks:

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

Test if assigning Date.now() to a variable and than calling it is faster than calling Date.now().

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

Created: one year ago by: Guest

Jump to the latest result

Date.now()

now()

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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