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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
Go to the latest result
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>
Run tests (3)
Previous results
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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
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Embed
Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=521456" width="100%" height="500px"></iframe>
double-bang
26.7M/s
undefined directly
10.7M/s
cast
10.6M/s
View exact numbers
Test name
Executions per second
✓
double-bang
26,747,858 Ops/sec
undefined directly
10,719,766 Ops/sec
cast
10,649,933 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
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.
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double-bang-vs-boolean-cast
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