Benchmark: Comparing null vs undefined 2

Script Preparation code:

var x;

Tests:

null strict
x === null;
undefined strict
x === undefined;
null loose
x == null;
undefined loose
x == undefined;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
null strict
undefined strict
null loose
undefined loose

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:94.0) Gecko/20100101 Firefox/94.0

Browser/OS: Firefox 94 on Ubuntu

View result in a separate tab

Test name	Executions per second
null strict	896941120.0 Ops/sec
undefined strict	802293760.0 Ops/sec
null loose	818758848.0 Ops/sec
undefined loose	814582336.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases, explaining what's being tested, compared, and discussing the pros and cons of each approach.

**Benchmark Definition**

The benchmark is designed to compare the performance differences between using strict equality (`===`) and loose equality (`==`) when checking for `null` and `undefined` values in JavaScript. The benchmark definition provides two scripts: one with a declared variable `x` set to `null`, and another with a variable `x` set to `undefined`.

**Script Preparation Code**

The script preparation code is `var x;`, which declares an empty variable `x`. This creates a reference that can be used in the benchmark test cases.

**Html Preparation Code**

There is no html preparation code provided, which means that the benchmark is focused solely on JavaScript performance and does not consider other factors like DOM manipulation or network latency.

**Individual Test Cases**

The benchmark defines four test cases:

1. `null strict`: `x === null`
2. `undefined strict`: `x === undefined`
3. `null loose`: `x == null`
4. `undefined loose`: `x == undefined`

These test cases compare the performance of using strict equality (`===`) versus loose equality (`==`) when checking for `null` and `undefined` values.

**Library**

None of the test cases use a specific library, but they do rely on JavaScript's built-in `===` (strict equality) and `==` (loose equality) operators. The `var x;` declaration creates a new variable that is not explicitly initialized, which can lead to unexpected behavior in some browsers.

**Special JS Feature/Syntax**

None of the test cases use any special JavaScript features or syntax beyond the use of strict and loose equality operators.

**Performance Comparison**

The benchmark aims to compare the performance differences between using strict equality (`===`) versus loose equality (`==`) when checking for `null` and `undefined` values. The results will likely indicate that:

* Strict equality (`===`) is faster than loose equality (`==`) because it allows the browser to optimize away unnecessary checks.
* Both approaches are optimized by most modern browsers, but strict equality might be slightly faster due to its more explicit nature.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Strict Equality (`===`)**:
	+ Pros: Faster execution, more explicit code, and better performance in optimized browsers.
	+ Cons: May lead to more complex code, especially when dealing with null or undefined values.
* **Loose Equality (`==`)**:
	+ Pros: Easier to read and write code, especially for beginners or those using languages that don't support strict equality.
	+ Cons: Slower execution due to unnecessary checks, and may lead to performance issues in optimized browsers.

**Alternatives**

If you wanted to modify the benchmark to explore different approaches, here are some alternatives:

* Compare `===` vs. `!==` (strict inequality) for checking if a value is not null or undefined.
* Use a variable like `nullOrUndefined` and test its assignment with `x = null`, `x = undefined`, etc.
* Include a test case that checks the performance of using `x ?? null` (optional chaining) versus traditional loose equality (`==`) for checking if `x` is either null or undefined.

I hope this explanation helps!

Related benchmarks:

Comparing null vs undefined 2 (version: 0)

Comparing performance of: null strict vs undefined strict vs null loose vs undefined loose

Created: 3 years ago by: Guest

Jump to the latest result

null strict

undefined strict

null loose

undefined loose

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):