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concat vs spread .
(version: 2)
Comparing performance of:
concat vs spread
Created:
3 years ago
by:
Registered User
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Script Preparation code:
var array1 = Array(1_000).fill(1).map((_, i) => i % 2); var array2 = Array(1_000).fill(0).map((_, i) => i % 2);
Tests:
concat
array1.filter(x => x !== 0).concat(array2.filter(x => x !== 0));
spread
[...array1.filter(x => x !== 0), ...(array2.filter(x => x !== 0))];
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
concat
spread
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down what's being tested in the provided JSON benchmark. **Benchmark Definition** The JSON defines a benchmark named `concat vs spread` with two test cases: `concat` and `spread`. The script preparation code creates two arrays, `array1` and `array2`, each with 1000 elements. Half of the elements are set to 1 (using modulo 2) and half are set to 0. **Test Cases** The two test cases compare the performance of concatenating two filtered arrays using different approaches: 1. **Concat**: The benchmark definition uses the `concat()` method to combine the two filtered arrays: `array1.filter(x => x !== 0).concat(array2.filter(x => x !== 0))`. 2. **Spread**: The other test case uses the spread operator (`...`) to concatenate the two filtered arrays: `[...array1.filter(x => x !== 0), ...(array2.filter(x => x !== 0))]`. **Options Compared** The benchmark is comparing the performance of: * Using `concat()` versus using the spread operator * Filtering and concatenating arrays in different orders **Pros and Cons** **Concatenation using `concat()`** Pros: * Simple and straightforward syntax * Wide support across browsers and languages * Can be more readable for those familiar with the method Cons: * May incur additional overhead due to the creation of a new array object * Less efficient than spread operator in modern JavaScript engines (more on this later) **Spread Operator** Pros: * More efficient than concatenation using `concat()` as it avoids creating an intermediate array object * Faster execution time, especially for large arrays Cons: * May be less readable for those unfamiliar with the syntax * Less supported across older browsers or versions of JavaScript **Library Used (None)** There are no libraries used in this benchmark. The code only relies on built-in JavaScript features. **Special JS Feature/Syntax** The benchmark uses the spread operator (`...`), which is a relatively modern feature introduced in ECMAScript 2015 (ES6). It allows for more concise and expressive syntax when working with arrays, objects, and other iterable types. The use of this feature might limit compatibility with older browsers or versions of JavaScript. **Other Alternatives** For those interested in exploring alternative approaches, here are a few: * Using `reduce()` instead of concatenation: This can be an efficient way to combine arrays, especially when working with large datasets. * Using `for...of` loops: These can provide more control over iteration and filtering, but might incur additional overhead due to the explicit loop syntax. Keep in mind that the performance differences between these approaches may vary depending on the specific use case, JavaScript engine, and hardware.
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