Benchmark: double-bang-vs-boolean-vs-unfedined-cast

Script Preparation code:

var falsy = undefined

Tests:

double-bang
!!falsy
cast
Boolean(falsy)
undefined directly
falsy != undefined

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
double-bang
cast
undefined directly

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

Browser/OS: Chrome 124 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
double-bang	26747858.0 Ops/sec
cast	10649933.0 Ops/sec
undefined directly	10719766.0 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 JSON to understand what's being tested in this JavaScript microbenchmark.

**Benchmark Definition**
The benchmark is defined as a comparison between three approaches to test if a variable `x` is falsy:

1. Double bang (`!!x`)
2. Boolean cast (`Boolean(x)`)
3. Strict inequality with `undefined` (`falsy != undefined`)

The goal is to determine which approach performs better in terms of execution speed.

**Options Compared**

* Double bang (`!!x`): This method uses the double not operator, which negates a value and then immediately reverts it. The intention behind this is that if `x` is falsy, `!!x` will return `true`, and if `x` is truthy, `!!x` will return `false`.
* Boolean cast (`Boolean(x)`): This method simply converts the variable `x` to a boolean value. In JavaScript, undefined becomes false in a boolean context.
* Strict inequality with `undefined` (`falsy != undefined`): This approach checks if `x` is not equal to `undefined`.

**Pros and Cons**

* Double bang:
	+ Pros: Compact and simple code
	+ Cons: Can be slower due to the extra operations (negation, reversion)
* Boolean cast:
	+ Pros: Fast and straightforward
	+ Cons: May not work as expected for certain types of variables (e.g., NaN)
* Strict inequality with `undefined`:
	+ Pros: Fast and accurate for checking falsiness
	+ Cons: Requires explicit comparison with `undefined`, which can be less readable

**Library and Special JS Features**

There are no libraries explicitly mentioned in the provided JSON. However, the double bang operator (`!!`) is a special JavaScript feature used to negate a value.

**Other Considerations**

When working with falsy values, it's essential to consider the specific use case and requirements of your application. The chosen approach should be efficient, readable, and maintainable.

**Alternatives**

For testing falsiness in JavaScript, you can also explore other approaches, such as:

* Using the `typeof` operator to check if a variable is undefined
* Implementing a custom function to check for falsiness (e.g., using the `isFalsy()` method)
* Utilizing libraries like Lodash or other utility functions for more advanced testing

Keep in mind that each approach has its trade-offs, and the choice ultimately depends on your specific use case and requirements.

Related benchmarks:

double-bang-vs-boolean-vs-unfedined-cast (version: 0)

!!x vs Boolean(x) vs !==

Comparing performance of: double-bang vs cast vs undefined directly

Created: 2 years ago by: Guest

Jump to the latest result

double-bang

cast

undefined directly

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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