Benchmark: Date.now 1000ms vs setTimeout 1000ms

Tests:

Date.now for
const lastCall = Date.now(); let now = Date.now(); while(now - lastCall < 1000) { now = Date.now() }
setTimeout
const handle = setTimeout(() => { this.shouldRestart = true; }, 1000);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Date.now for
setTimeout

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:123.0) Gecko/20100101 Firefox/123.0

Browser/OS: Firefox 123 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Date.now for	1.0 Ops/sec
setTimeout	438014.8 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help explain the provided benchmark.

**What is tested:**
The benchmark measures the performance of two approaches to create a busy loop:

1. Using `Date.now()` in a while loop (`"Date.now for "`): This approach repeatedly checks the current time using `Date.now()` and increments a counter until 1000 milliseconds have passed.
2. Using `setTimeout()` with a callback function (`"setTimeout"`): This approach uses the `setTimeout()` function to schedule a function that will be executed after 1000 milliseconds, without explicitly looping.

**Options compared:**
The benchmark compares two options:

1. **Busy loop using `Date.now()`:** This approach creates a busy loop by repeatedly checking the current time and incrementing a counter. It uses the `while` loop to wait for 1000 milliseconds.
2. **Using `setTimeout()` with a callback function:** This approach schedules a function to be executed after 1000 milliseconds using `setTimeout()`. The callback function is executed without any explicit looping.

**Pros and Cons:**

* **Busy loop using `Date.now()`:**
	+ Pros:
		- Simple and straightforward implementation.
		- Can be easily optimized by reducing the frequency of `Date.now()` calls.
	+ Cons:
		- May consume more CPU resources due to repeated checks on the current time.
		- Can be affected by system clock accuracy and resolution.
* **Using `setTimeout()` with a callback function:**
	+ Pros:
		- More efficient than busy loops, as the browser's scheduling mechanism can handle the timing for you.
		- Allows for better control over the execution of code, such as scheduling multiple callbacks.
	+ Cons:
		- Requires more setup and understanding of the `setTimeout()` API.

**Library and syntax:**
The benchmark uses no external libraries. However, it does use some JavaScript-specific features:

* **Arrow functions (`=>`):** Used in the callback function for `setTimeout()`.
* **Template literals (`\r\n` and `\n`):** Used to define the script preparation code.

**Other alternatives:**

* Another approach to create a busy loop could be using `setInterval()` instead of `while` loops. This would achieve similar results but with a more explicit timing mechanism.
* If you need to perform multiple iterations, consider using `Promise.all()` or similar constructs to parallelize the execution and potentially improve performance.

In general, when writing benchmarks, it's essential to consider factors such as:

* System clock accuracy and resolution
* Browser-specific optimizations (e.g., WebKit's timing code)
* CPU resource utilization
* Memory usage

By understanding these factors, developers can optimize their code for better performance and more efficient execution.

Related benchmarks:

Date.now 1000ms vs setTimeout 1000ms (version: 0)

Comparing performance of: Date.now for vs setTimeout

Created: 2 years ago by: Guest

Jump to the latest result

Date.now for

setTimeout

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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