Benchmark: ArrayBuffer.isView vs instanceof

HTML Preparation code:

<script>
  const buffer = crypto.getRandomValues(new Uint8Array(10))
  const nobuffer = [...Array(10).keys()]
</script>

Tests:

ArrayBuffer.isView true
ArrayBuffer.isView(buffer)
instanceof true
buffer instanceof Uint8Array
ArrayBuffer.isView false
ArrayBuffer.isView(nobuffer)
instanceof false
nobuffer instanceof Uint8Array

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
ArrayBuffer.isView true
instanceof true
ArrayBuffer.isView false
instanceof false

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the benchmark and explain what's being tested.

The benchmark is comparing two ways to check if an `ArrayBuffer` object is a view of another object:

1. `ArrayBuffer.isView(buffer)`: This method checks if the given `buffer` is a view of another object, i.e., if it shares the same underlying array.
2. `buffer instanceof Uint8Array`: This method checks if the given `buffer` is an instance of `Uint8Array`, which is a typed array class that inherits from `ArrayBuffer`.

**Options compared:**

The benchmark is comparing the performance of these two approaches on different test cases.

* Test case 1: `ArrayBuffer.isView(true)`, where `buffer` is a view of another object.
* Test case 2: `instanceof true`, where `buffer` is an instance of `Uint8Array`.
* Test case 3: `ArrayBuffer.isView(false)`, where `buffer` is not a view of another object.
* Test case 4: `instanceof false`, where `buffer` is not an instance of `Uint8Array`.

**Pros and Cons of each approach:**

1. `ArrayBuffer.isView(buffer)`:
	* Pros:
		+ More accurate, as it checks if the buffer shares the same underlying array.
		+ May be faster for certain use cases, such as when working with large buffers.
	* Cons:
		+ Can be slower than `instanceof` in some cases, especially when dealing with small buffers or arrays that are not contiguous in memory.
2. `buffer instanceof Uint8Array`:
	* Pros:
		+ Faster and more concise than `ArrayBuffer.isView(buffer)`.
		+ Widely supported and understood by developers.
	* Cons:
		+ May not be accurate, as it only checks if the buffer is an instance of `Uint8Array`, without checking if it's a view.

**Library usage:**

The benchmark uses the `crypto` module to generate random data for the test cases. The `getRandomValues` method returns a typed array of random values, which is used to create the `buffer` variable.

**Special JavaScript feature or syntax:**

There are no special JavaScript features or syntaxes being tested in this benchmark.

**Alternative approaches:**

1. Using `Buffer.isBuffer(buffer)`: This method checks if the given buffer is an instance of `Buffer`, but it may not be accurate for all cases, as it doesn't check if the buffer is a view.
2. Using `Array.isArray(buffer)` and then checking the type of each element in the array: This approach can be slower than `instanceof` and may not be accurate, especially when dealing with large arrays or buffers.

In summary, the benchmark is comparing two ways to check if an `ArrayBuffer` object is a view of another object. While `ArrayBuffer.isView(buffer)` provides more accuracy, it may be slower than `buffer instanceof Uint8Array`. The choice of approach depends on the specific use case and performance requirements.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/117.0

Browser/OS: Firefox 117 on Windows

View result in a separate tab

Test name	Executions per second
ArrayBuffer.isView true	66358192.0 Ops/sec
instanceof true	114211728.0 Ops/sec
ArrayBuffer.isView false	57666960.0 Ops/sec
instanceof false	92399304.0 Ops/sec

Related benchmarks:

ArrayBuffer.isView vs instanceof (version: 0)

Comparing performance of: ArrayBuffer.isView true vs instanceof true vs ArrayBuffer.isView false vs instanceof false

Created: 4 years ago by: Guest

Jump to the latest result

ArrayBuffer.isView true

instanceof true

ArrayBuffer.isView false

instanceof false

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):