Benchmark: Array isArray vs Object.prototype

Script Preparation code:

var test = [1,2,3,4];
var c;

Tests:

Object.prototype
if (Object.prototype.toString.call(test) === '[object Array]') { c++; }
isArray
if (Array.isArray(test)) { c++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.prototype
isArray

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36 Edg/122.0.0.0

Browser/OS: Chrome 122 on Windows

View result in a separate tab

Test name	Executions per second
Object.prototype	2777091.2 Ops/sec
isArray	2653699.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what's being tested.

**Benchmark Definition**

The benchmark is testing two approaches to check if an array or object is an array:

1. `Object.prototype.toString.call(test) === '[object Array]'`
2. `Array.isArray(test)`

These two methods are used in JavaScript to determine if a value is an array.

**Options compared**

We have two options being compared:

A) Using the `Object.prototype.toString()` method, which checks if the string representation of the object is `[object Array]`.

B) Using the `Array.isArray()` method, which returns a boolean indicating whether the input value is an array.

**Pros and Cons**

* **Option A (Object.prototype.toString())**: This approach has the following pros and cons:
	+ Pros: It's a widely used and well-known method in JavaScript.
	+ Cons: It can be slower than `Array.isArray()` due to the overhead of calling `toString()` and comparing the result with `[object Array]`.
* **Option B (Array.isArray())**: This approach has the following pros and cons:
	+ Pros: It's generally faster than using `Object.prototype.toString()`, as it only checks if the input value is an array object without performing any additional string operations.
	+ Cons: While widely used, some older browsers or environments might not support this method.

**Library usage**

There is no explicit library being used in this benchmark. However, both methods rely on the `Array` and `Object` constructors, which are part of the JavaScript standard library.

**Special JS feature or syntax**

None of the methods mentioned require any special JavaScript features or syntax beyond what's available in the JavaScript standard library.

**Other alternatives**

If you were to implement this benchmark using a different approach, some alternative options could be:

* Using `typeof` operator with a string literal: `typeof test === 'object' && typeof test === 'array'`
* Implementing a custom array check function
* Comparing the performance of different JavaScript engines or browsers

However, these alternatives would require significant changes to the benchmark and might not provide comparable results.

Keep in mind that this benchmark is testing two well-established methods for checking if an object is an array. The primary goal is to measure their relative performance in modern JavaScript environments.

Related benchmarks:

Array isArray vs Object.prototype (version: 0)

Comparing performance of: Object.prototype vs isArray

Created: 2 years ago by: Guest

Jump to the latest result

Object.prototype

isArray

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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