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Array.prototype.concat vs spread operator [huge collection] 2
(version: 0)
Comparing performance of:
.concat vs spread
Created:
3 years ago
by:
Guest
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Script Preparation code:
biglist = new Array(1e6).fill(null).map(_ => Math.random() + 'x')
Tests:
.concat
console.log(biglist.concat(biglist)[biglist.length])
spread
console.log([...biglist, ...biglist][biglist.length])
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
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the test case and explain what's being tested. **Benchmark Definition** The benchmark is comparing two ways to concatenate (join) an array in JavaScript: the `concat()` method and the spread operator (`...`). **Script Preparation Code** The script preparation code generates a large array of 1 million elements, where each element is a random string in the format "x". This array is assigned to the variable `biglist`. **Html Preparation Code** There is no HTML preparation code provided, which means that the benchmark is likely running in a headless browser or on the client-side. **Test Cases** The benchmark consists of two test cases: 1. `.concat`: Tests the performance of using the `concat()` method to concatenate the `biglist` array. 2. `spread`: Tests the performance of using the spread operator (`...`) to concatenate the `biglist` array. **Library and Framework** None are specified in this benchmark definition. **Special JS Features or Syntax** The use of the spread operator (`...`) is a relatively recent feature introduced in ECMAScript 2015 (ES6). It allows for more concise and expressive way of copying arrays, but its performance can vary depending on the browser and implementation. **Pros and Cons** **.concat:** Pros: * Wide support across older browsers * Less CPU-intensive than spread operator Cons: * Less readable and maintainable code * Can be slower in modern browsers that optimize `concat()` internally **spread:** Pros: * More concise and expressive code * Faster execution time due to optimized implementations by browsers Cons: * Requires support for ES6 features, which can be a limitation in older browsers * Can be slower in older browsers or environments with limited JavaScript engine optimizations **Other Considerations** The use of `console.log()` for output is not ideal for benchmarking, as it can introduce additional overhead due to the logging process. A more accurate and efficient way would be to measure the time taken by the browser to execute the code directly. It's also worth noting that the `biglist` array is generated with random strings, which means the benchmark results may vary depending on the specific content of the array. **Alternatives** Some alternatives for similar benchmarks could include: * Using a smaller array size to reduce computational overhead * Adding more test cases to cover other concatenation methods or algorithms (e.g., `Array.prototype.push()`, `setInterval()` with `concat()`) * Using a different data structure, such as an object or set, for concatenation Keep in mind that the specific approach and alternatives will depend on the goals and requirements of the benchmark.
Related benchmarks:
Array.prototype.concat vs spread operator - Immutable version
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Array.prototype.concat vs spread operator - large arrays
Array.prototype.concat vs spread operator vs flat [huge collection]
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