Benchmark: null checking - MeasureThat.net

Script Preparation code:

var x = undefined, y = null, z = {x:1, y:2};

Tests:

bool check
var res = (!x) || (!y) || (!z);
null check
var res = (x == null) || (y == null) || (z == null);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
bool check
null check

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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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 is being tested, compared, and discussed.

**Benchmark Overview**

The benchmark is designed to measure the performance of JavaScript in terms of null checking. The test case checks if a variable is null or not using two different approaches: boolean OR operator (`||`) and equality comparison with `null` (`== null`).

**Script Preparation Code**

The script preparation code defines three variables:
```javascript
var x = undefined, y = null, z = {x:1, y:2};
```
Here, we have:

* `x`: set to `undefined`, which is the JavaScript equivalent of null.
* `y`: set to `null`.
* `z`: an object with two properties: `x` (set to 1) and `y` (set to 2).

**Html Preparation Code**

There is no HTML preparation code provided, so we can skip this part.

**Test Cases**

The benchmark consists of two test cases:

1. **bool check**
```javascript
var res = (!x) || (!y) || (!z);
```
This test case checks if the variables `x`, `y`, and `z` are all null using the boolean OR operator (`||`). The expression `(!x)` evaluates to true (since `x` is undefined), and since the OR operator returns false only when both operands are false, the overall result will be true.

2. **null check**
```javascript
var res = (x == null) || (y == null) || (z == null);
```
This test case checks if any of the variables `x`, `y`, and `z` are equal to `null` using the equality comparison operator (`==`). The expression `(x == null)` evaluates to true if `x` is indeed null.

**Pro/Cons**

The main difference between these two approaches lies in how they handle the cases where only one variable is null:

* **bool check**: If any of the variables are undefined, the overall result will be true. This might lead to unexpected behavior in certain situations.
* **null check**: If only one variable is null, the overall result will be true.

The pros and cons of each approach depend on the specific use case:

* `bool check`:
	+ Pros: more concise and readable code
	+ Cons: may lead to unexpected behavior if any variable is undefined
* `null check`:
	+ Pros: avoids potential issues with undefined variables, but might be less readable
	+ Cons: requires explicit comparison with null

**Library Usage**

There are no libraries used in this benchmark.

**Special JS Features/Syntax**

None mentioned.

**Other Alternatives**

Other approaches to null checking in JavaScript include:

* Using the `?.` optional chaining operator (introduced in ECMAScript 2020):
```javascript
var res = (!x?.x || !y?.y || !z?.x);
```
This approach avoids issues with undefined variables and provides a more concise way to check for null values.

Keep in mind that these alternatives may not be supported by older browsers or JavaScript engines, so it's essential to test your code thoroughly across different environments.

Related benchmarks:

null checking (version: 0)

Comparing performance of: bool check vs null check

Created: 4 years ago by: Guest

Jump to the latest result

bool check

null check

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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