Benchmark: new Date vs performance.now

Tests:

new Date
new Date().getTime()
performance.now
performance.now()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Date
performance.now

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.90 Safari/537.36

Browser/OS: Chrome 89 on Mac OS X 10.14.6

View result in a separate tab

Test name	Executions per second
new Date	3643511.0 Ops/sec
performance.now	2875368.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases to understand what is being tested.

**Benchmark Definition JSON:**

The `Name` field specifies that the benchmark is comparing two approaches: `new Date().getTime()` and `performance.now()`. The `Description` field provides a brief explanation of the benchmark, which is to compare the overhead of these two functions. There are no additional fields specified, so we can infer that there's no specific context or setup required for the benchmark.

**Individual Test Cases:**

The provided test cases are:

1. `new Date()`: This function creates a new `Date` object and returns its time value.
2. `performance.now()`: This function returns the number of milliseconds since the Unix Epoch (January 1, 1970, 00:00:00 UTC) as a high-resolution timer.

**What is being tested?**

The benchmark is testing the overhead or performance difference between these two functions when used to measure time. In essence, it's measuring how quickly each function can return a value representing the current time.

**Options compared:**

Here are the options being compared:

1. `new Date().getTime()`: This method creates a new `Date` object and returns its time value. The overhead of creating an object is introduced by this approach.
2. `performance.now()`: This function is specifically designed to provide high-resolution timing without introducing unnecessary object creation.

**Pros and Cons:**

**Option 1 (`new Date().getTime()`):**

Pros:

* Simpler implementation, potentially requiring less code or optimization effort.
* May be easier to understand for developers who are not familiar with performance-critical timing functions.

Cons:

* Introduces unnecessary object creation, which can be costly in terms of performance and memory usage.
* May lead to slower results due to the overhead of creating a `Date` object.

**Option 2 (`performance.now()`):**

Pros:

* Designed for high-resolution timing with minimal overhead.
* Typically faster and more efficient than option 1.

Cons:

* May require additional setup or library inclusion (in this case, none is needed).
* Requires knowledge of the function's existence and behavior to use correctly.

**Library:**

None. The `performance.now()` function is a built-in JavaScript method that doesn't rely on any external libraries.

**Special JS feature/syntax:**

None mentioned in the provided code snippets.

**Other considerations:**

When writing performance-critical timing functions, it's essential to consider the trade-offs between simplicity, readability, and performance. In this case, `performance.now()` is generally a better choice due to its optimized implementation and minimal overhead.

For developers new to JavaScript or performance-critical programming, understanding the difference between these options can help them write more efficient code.

**Alternatives:**

Other alternatives for measuring time in JavaScript include:

1. `Date.now()`: Similar to `performance.now()`, but not as high-resolution.
2. `requestAnimationFrame()` or `setTimeout()` with a callback function: These can be used to measure the passage of time between events, but may not provide the same level of precision as `performance.now()`.
3. External libraries like HighPerformanceJs or jsperf: These can provide more advanced timing and benchmarking capabilities, but may add overhead and complexity.

Keep in mind that these alternatives may not always be suitable for every use case, and understanding their trade-offs is essential to making informed decisions.

Related benchmarks:

new Date vs performance.now (version: 0)

Compares the overhead of new Date().getTime() and performance.now().

Comparing performance of: new Date vs performance.now

Created: 3 years ago by: Registered User

Jump to the latest result

new Date

performance.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):