Benchmark: instanceof vs null

Script Preparation code:

var obj = {};

Tests:

intance
obj instanceof Object
null
obj === null

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
intance
null

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36 Edg/126.0.0.0

Browser/OS: Chrome 126 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
intance	11179979.0 Ops/sec
null	28222014.0 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 benchmark and explain what's being tested.

**Benchmark Purpose**

The primary purpose of this benchmark is to compare the performance of JavaScript code that checks if an object is an instance of the `Object` class versus simply checking if it's equal to `null`.

**Comparison Options**

Two options are compared in this benchmark:

1. `obj instanceof Object`: This option checks if the `obj` variable is an instance of the `Object` class, which means it must have at least one of its own properties (like `toString()`, `constructor`, etc.) or be a function.
2. `obj === null`: This option simply checks if the `obj` variable is equal to `null`.

**Pros and Cons**

* **`obj instanceof Object`**:
	+ Pros: More accurate, as it checks for specific properties and constructor functions that define an object.
	+ Cons: May be slower due to additional checks.
* **`obj === null`**:
	+ Pros: Fastest option, as it only checks for equality with `null`.
	+ Cons: Less accurate, as it doesn't consider the presence of other properties.

**Library and Special JS Features**

There is no explicit library mentioned in this benchmark. However, the use of `instanceof` operator implies that the JavaScript engine being tested supports this operator.

The `instanceof` operator is a special feature introduced in ECMAScript 5 (ES5) that allows checking if an object is an instance of a particular constructor function or class.

**Other Considerations**

When writing performance-critical code, developers often need to consider these factors:

* **Null checks**: In some cases, null checks can be slower than other methods. However, in many situations, the difference is negligible.
* **Object property access**: When working with objects, accessing specific properties or checking if an object has certain properties can have a performance impact.

**Alternatives**

If you're interested in exploring alternative approaches for comparing objects to `null` or `undefined`, consider the following options:

* Using `typeof` operator instead of `instanceof`: `typeof obj === 'object'`
* Using a custom function to check if an object is null or undefined
* Using a library like Lodash's `isNil()` function

Keep in mind that these alternatives may not provide identical performance characteristics as the `instanceof` operator.

I hope this explanation helps you understand what's being tested in this benchmark!

Related benchmarks:

instanceof vs null (version: 0)

Comparing performance of: intance vs null

Created: 5 years ago by: Guest

Jump to the latest result

intance

null

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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