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array index hint comparison, logical sum vs declaration
(version: 1)
Comparing performance of:
logical sum hint vs annotation on declaration
Created:
one year ago
by:
Registered User
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Tests:
logical sum hint
let i = 0; let array = Array(100000); while (i < array.length) { array[i] = i; i = (i + 1)|0; }
annotation on declaration
let i = 0n; let array = Array(100000); while (i < array.length) { array[i] = i; i = i + 1n; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
logical sum hint
annotation on declaration
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/136.0.0.0 Safari/537.36
Browser/OS:
Chrome 136 on Windows
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<iframe src="https://measurethat.net/Embed?id=604905" width="100%" height="500px"></iframe>
logical sum hint
3K/s
annotation on declaration
55/s
View exact numbers
Test name
Executions per second
✓
logical sum hint
2,988 Ops/sec
annotation on declaration
55 Ops/sec
Autogenerated LLM Summary
(model
gpt-4o-mini
, generated one year ago):
The benchmark defined in the provided JSON is focused on comparing two different coding styles that affect the performance of a loop that populates an array with sequential integers. The two approaches being tested are: 1. **Logical Sum Hint**: - **Test Code**: ```javascript let i = 0; let array = Array(100000); while (i < array.length) { array[i] = i; i = (i + 1)|0; } ``` - **Description**: In this test, the variable `i` is incremented using a bitwise OR operation (`|0`), which effectively casts `i` to a 32-bit integer. This technique may help JavaScript engines optimize the loop by providing a hint about the type of the variable. 2. **Annotation on Declaration**: - **Test Code**: ```javascript let i = 0n; let array = Array(100000); while (i < array.length) { array[i] = i; i = i + 1n; } ``` - **Description**: In this test, `i` is declared as a BigInt (`0n`). BigInt allows representation of large integers that are outside the range of the regular Number type in JavaScript. The loop uses the BigInt increment operation (`i = i + 1n`). ### Performance Comparison and Insights - **Executions Per Second**: - **Logical Sum Hint**: 2987.91 executions per second - **Annotation on Declaration**: 54.88 executions per second ### Pros and Cons of Each Approach - **Logical Sum Hint**: - **Pros**: - Significantly faster execution time, as indicated by the benchmark results. - Leverages JavaScript engine optimizations for integer operations. - **Cons**: - The use of `|0` may reduce code readability for less experienced developers who are not familiar with bitwise operations. - **Annotation on Declaration**: - **Pros**: - Allows handling very large integers, which can be useful in specific scenarios that require mathematical precision beyond the typical floating-point representation. - Can be more readable and straightforward for developers familiar with BigInt. - **Cons**: - Much slower execution time; not suitable for time-critical applications where performance is paramount. - May introduce additional complexity in scenarios where BigInts are not necessary. ### Other Considerations - **Choice of Data Type**: Decision-makers should consider the context in which the array is being used. For most typical scenarios that don't involve large integers, using standard Number types (and the logical sum hint approach) would likely yield better performance. - **Memory and Performance**: Using a large array (like `Array(100000)`) can lead to increased memory consumption that could affect performance depending on the application's context and the available environment (e.g., browser or device). ### Alternatives Other alternatives to implement similar functionality include: - **For Loop**: Using a standard for loop (`for (let i = 0; i < array.length; i++)`) could be easier to read and might have varying performance characteristics depending on JavaScript engine optimizations. - **Array Methods**: While not directly comparable to the raw speed of manually populated loops, methods like `.fill()` or `.map()` for populating arrays can result in cleaner code, with trade-offs in performance. In summary, the benchmark illustrates the impact of coding style on performance in JavaScript, demonstrating how simple changes can yield significant differences in execution speed.
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