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array.length vs array.length > 0 v2
(version: 1)
Comparing performance of:
array length vs array length > 0
Created:
one year ago
by:
Guest
Jump to the latest result
Script Preparation code:
var arr = [];
Tests:
array length
if (!!arr.length) { console.log(1); } else { console.log(0); }
array length > 0
if (arr.length > 0) { console.log(1); } else { console.log(0); }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
array length
array length > 0
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Edg/131.0.0.0
Browser/OS:
Chrome 131 on Windows
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=570834" width="100%" height="500px"></iframe>
Test name
Executions per second
array length
192550.5 Ops/sec
array length > 0
191726.5 Ops/sec
Autogenerated LLM Summary
(model
gpt-4o-mini
, generated one year ago):
The benchmark defined in the JSON provided compares two different expressions used to check if an array is non-empty: `arr.length` and `arr.length > 0`. The purpose of this benchmark is to measure the performance difference between two common ways to determine whether an array contains any elements. ### Test Cases and Methods Compared 1. **Test Case 1: `if (!!arr.length)`** - **Test Name:** `array length` - This test case uses the double negation operator (`!!`) to convert the `arr.length` value into a boolean. In JavaScript, the length of an array is a number, and using `!!` converts any non-zero number (including the array's length if it has elements) to `true`, while zero becomes `false`. 2. **Test Case 2: `if (arr.length > 0)`** - **Test Name:** `array length > 0` - This test checks if the length of the array is greater than zero directly. If `arr.length` is greater than zero, it means the array has one or more elements, thus returning `true`. ### Performance Results The benchmark results provide the number of executions per second for each method: - **`array length`** achieved approximately **466,011 executions per second**. - **`array length > 0`** achieved approximately **427,487 executions per second**. From this data, we can conclude that the method using `!!arr.length` is slightly more performant in this specific test case. ### Pros and Cons of Each Approach - **Using `!!arr.length`**: - **Pros**: - Slightly faster as indicated by the benchmark results. - More concise, reducing the amount of visible code. - **Cons**: - May be less readable to those unfamiliar with JavaScript's coercion rules and the double negation trick. - **Using `arr.length > 0`**: - **Pros**: - More intuitive and explicit for many developers, making it clearer that we're specifically looking for non-empty arrays. - Easier to understand for those who may not be deeply familiar with JavaScript’s type coercion. - **Cons**: - Marginally slower based on the results, which, while often negligible, could be relevant in performance-critical applications. ### Other Considerations While the benchmark demonstrates a difference in performance between two expressions, the choice between them should also consider readability and maintainability. In many cases, prioritizing code clarity over micro-optimizations is advisable because the performance difference is minimal and might not impact overall application performance significantly. ### Alternatives Other alternatives to check for an empty array could include: - **Using `Array.isArray()` to verify** if a variable is an array and then checking the length. This introduces additional overhead but can be useful for type safety, especially when handling mixed data types. - **Using a custom utility function**: Development of a function that encapsulates this logic allows for more descriptive intentions in code and eases future maintenance, though it adds to the function call overhead. In general, benchmarks such as this serve as a way for developers to assess performance trade-offs but should always be balanced against the needs for clear and maintainable code.
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