Benchmark: if not strong null vs !!

Script Preparation code:

var obj = {};

Tests:

!= null
if(obj.s != null) { var b = 1; }
false
if(!!obj.s) { var b = 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
!= null
false

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in this benchmark and the different approaches compared.

**What is being tested?**

The benchmark is testing two different ways to check if an object has a property that is not null: using the `!=` operator versus the `!!` operator (also known as the "double bang" operator).

In the first test case, the code checks if `obj.s` is not equal to null (`obj.s != null`). In the second test case, the code checks if `obj.s` is falsy using the `!!` operator, which converts the value to a boolean. If `obj.s` is an object or array, `!!` will return false, and if it's null, `!!` will return false.

**Options compared**

There are two options being compared:

1. `obj.s != null`: This checks if the property exists on the object and its value is not null. If the property doesn't exist, this expression will evaluate to true.
2. `!!obj.s`: This converts the value of `obj.s` to a boolean using the `!!` operator. This works because in JavaScript, null and undefined are considered falsy values.

**Pros and cons**

Here's a brief summary of the pros and cons of each approach:

* `obj.s != null`:
	+ Pros: straightforward and easy to read.
	+ Cons: may be slower since it involves a property check and a comparison with null.
* `!!obj.s`:
	+ Pros: can be faster since it only requires a single operation (converting the value to a boolean).
	+ Cons: less intuitive and more prone to errors if not used correctly.

**Library usage**

There is no explicit library being used in this benchmark. However, some browsers may use their own optimizations or caching mechanisms that could affect the results. For example, Chrome's just-in-time (JIT) compiler may optimize the `!!` operator.

**Special JavaScript features**

The benchmark doesn't specifically target any special JavaScript features like ES6 syntax or modern language features. It only tests two simple and well-known ways to check for null values in an object.

**Alternative approaches**

If you wanted to add more test cases, here are some alternative approaches:

* `obj.s === undefined`: This checks if the property exists on the object but its value is not set.
* `!!(obj.s || false)`: This uses the OR operator (`||`) and then converts the result to a boolean using `!!`.
* `obj.hasOwnProperty('s') && obj.s !== null`: This checks if the object has the property 's' and its value is not null.

Keep in mind that these alternative approaches may have different performance characteristics or readability, depending on your use case.

Related benchmarks:

if not strong null vs !! (version: 0)

which is faster

Comparing performance of: != null vs false

Created: 3 years ago by: Guest

Jump to the latest result

!= null

false

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):