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werwerwe
(version: 0)
Comparing performance of:
length - 1 vs at method
Created:
2 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
var arr = ['1', '2', '3'];
Tests:
length - 1
console.log(arr.length - 1)
at method
console.log(arr.at(-1))
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
length - 1
at method
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
2 years ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36
Browser/OS:
Chrome 123 on Windows
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<iframe src="https://measurethat.net/Embed?id=515684" width="100%" height="500px"></iframe>
Test name
Executions per second
length - 1
107363.5 Ops/sec
at method
105175.3 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the benchmark test and explain what's being tested, the different approaches, their pros and cons, and other considerations. **Benchmark Test Overview** The test measures the performance of two JavaScript operations: accessing the last element of an array using the `length - 1` approach versus the `at(-1)` method. The test is run on a Chrome browser with Windows platform. **Script Preparation Code** The script preparation code defines a constant array `arr` with three elements: `[ '1', '2', '3' ]`. This array will be used as input for both benchmark operations. **Benchmark Operations** There are two benchmark operations: 1. **length - 1**: This operation accesses the last element of the `arr` array by subtracting 1 from its length. ```javascript console.log(arr.length - 1); ``` 2. **at method**: This operation uses the `at()` method to access the last element of the `arr` array directly. ```javascript console.log(arr.at(-1)); ``` **Pros and Cons** * **length - 1**: + Pros: Simple and widely supported in older browsers. + Cons: May be slower due to the need for additional calculations. * **at method**: + Pros: More efficient and modern, as it's a built-in method for arrays. + Cons: May not be supported in older browsers. **Library and Purpose** In this benchmark test, there is no explicit library being used. However, the `at()` method is a part of the ECMAScript Standardized Specification (ECMAScript 2020), which means it's a standard JavaScript feature. **Other Considerations** * **Cache efficiency**: The `length - 1` approach may have better cache locality due to its simplicity, while the `at(-1)` method may incur more cache misses due to its indirect access. * **Branch prediction**: Modern CPUs use branch prediction to optimize performance. However, the `length - 1` approach may not benefit from good branch prediction due to its variable nature (depending on the array's length). **Alternatives** If you wanted to test alternative approaches, some options could be: * Using a different data structure, such as an object or a string, instead of an array. * Adding additional complexity to the benchmark operations, such as nested loops or recursive calls. * Comparing the performance of different JavaScript engines, such as V8 (Chrome) vs. SpiderMonkey (Firefox). Keep in mind that these alternatives would require significant changes to the benchmark test and may not provide meaningful results. I hope this explanation helps you understand what's being tested in the benchmark!
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