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Copy and push vs spread
(version: 0)
Comparing performance of:
Copy and push vs Spread
Created:
4 years ago
by:
Guest
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Script Preparation code:
var arr = [1, "2", true];
Tests:
Copy and push
const arrCopy = arr.slice(0); arrCopy.push("4");
Spread
const arrCopy = [...arr, "4"];
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
Copy and push
Spread
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
**Benchmark Overview** MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided benchmark compares two approaches for performing a simple operation: copying an array and pushing a new element onto it, versus using the spread operator to create a new array. **Tested Options** The benchmark tests two options: 1. **Copy and push**: This approach uses the `slice()` method to create a shallow copy of the original array, and then pushes a new element onto the copied array. 2. **Spread**: This approach uses the spread operator (`...`) to create a new array that includes all elements from the original array, followed by the new element. **Pros and Cons** * **Copy and push**: + Pros: Simple and intuitive approach, easy to understand for beginners. + Cons: Creates an extra copy of the array, which can lead to performance issues if the array is large or if many copies need to be made. This approach also requires multiple operations (copying and pushing), which can increase overhead. * **Spread**: + Pros: More efficient than creating a new array using `slice()`, as it avoids an extra copy of the original array. Also, creates a new array with a single operation. + Cons: Requires understanding of the spread operator syntax (`...`), which might be unfamiliar to some developers. **Library and Special JS Features** * **Spread operator**: The spread operator is a built-in JavaScript feature that allows creating a new array by including elements from an existing array. It was introduced in ECMAScript 2015 (ES6) as part of the standard language. * **Slice method**: The `slice()` method is also a built-in JavaScript function that returns a shallow copy of a portion of an array. **Other Considerations** * **Array size and complexity**: If the input array is large or complex, creating a new array with many elements (as in the spread approach) might be more efficient than copying and pushing. * **Performance overhead**: Creating multiple copies of the original array (as in the copy and push approach) can lead to performance issues due to the extra memory allocation and garbage collection. **Alternatives** Other approaches could be explored, such as: 1. Using `Array.prototype.concat()` or other array methods that avoid creating a new array. 2. Utilizing specialized libraries or tools for benchmarking JavaScript performance (e.g., Google Benchmark). 3. Implementing the benchmark in a language with better performance characteristics (e.g., C++). Keep in mind that JavaScript is an interpreted language, and its performance characteristics can be influenced by many factors, such as engine optimizations, caching, and garbage collection. The best approach depends on the specific requirements of the use case and the expected workload.
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