Benchmark: isArray property check

Script Preparation code:

var no = {};
var yes = [{}];

Tests:

Array.isArray
Array.isArray(no); Array.isArray(yes);
.push != null
no.push !== undefined; yes.push !== undefined;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.isArray
.push != null

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36

Browser/OS: Chrome 116 on Linux

View result in a separate tab

Test name	Executions per second
Array.isArray	3277452.5 Ops/sec
.push != null	3406950.5 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 benchmark definition and test cases.

**What is tested?**

The benchmark measures the performance of two JavaScript properties:

1. `Array.isArray`: checks if a given value is an array.
2. `.push != null`: checks if the `push` method is not undefined on an array or object.

**Options compared:**

There are two test cases, each comparing different options:

1. `Array.isArray(no); Array.isArray(yes);`
2. `no.push !== undefined; yes.push !== undefined;`

These tests check how quickly the JavaScript engine can execute these property checks.

**Pros and Cons of different approaches:**

1. **`Array.isArray(no); Array.isArray(yes);`**
	* Pros:
		+ Tests the `Array.isArray` method, which is a built-in array checking function.
		+ Easy to understand and implement.
	* Cons:
		+ Requires explicit checks for arrays using this method, which may not be the most efficient way to check if a value is an array.
2. **`no.push !== undefined; yes.push !== undefined;`**
	* Pros:
		+ Tests the `.push` method, which is a more direct way to check if a method exists on an object or array.
		+ May be faster than using `Array.isArray`, as it's a direct method call.
	* Cons:
		+ Requires explicit checks for methods, which may not be the most efficient way to check if a value has a certain property.

**Library usage:**

There is no library usage in this benchmark definition. The tests only use built-in JavaScript properties and methods.

**Special JS features or syntax:**

This benchmark does not test any special JavaScript features or syntax.

**Other alternatives:**

If you were to rewrite this benchmark, you could consider alternative approaches:

1. **Using `typeof`**: Instead of using `Array.isArray`, you could use `typeof value === 'object' && Array.prototype instanceof Object`. This checks if the value is an object and if it's an array.
2. **Using a loop**: You could create a loop that iterates over a large array or object, and then checks if each element is an array using `Array.isArray`.
3. **Using WebAssembly**: If you want to test performance in a more controlled environment, you could use WebAssembly (WASM) and write native code to perform the property checks.

Keep in mind that these alternatives may not be as straightforward or easy to implement as the original benchmark, but they could provide valuable insights into different aspects of JavaScript performance.

Related benchmarks:

isArray property check (version: 0)

Can you beat it?

Comparing performance of: Array.isArray vs .push != null

Created: one year ago by: Registered User

Jump to the latest result

Array.isArray

.push != null

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):