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Slice vs spread array
(version: 0)
Measure which of the two options is a faster shallow copy
Comparing performance of:
Slice vs Spread
Created:
3 years ago
by:
Guest
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Script Preparation code:
var originalArray = [0, 1, 2, 'zero', 'one', 'two', false, true, true];
Tests:
Slice
const copyArray = originalArray.slice();
Spread
const copyArray = [...originalArray];
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
Slice
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):
I'll break down the provided benchmark definition and test cases to explain what's being tested, the options compared, their pros and cons, and other considerations. **Benchmark Definition** The `Slice vs spread array` benchmark is designed to measure which approach creates a shallow copy of an array faster: using the `.slice()` method or the spread operator (`...`). The benchmark aims to determine if one approach is consistently faster than the other across different browsers and devices. **Options Compared** Two options are compared: 1. **Slice**: Uses the `.slice()` method, which returns a new array that contains all elements from the original array, without modifying it. 2. **Spread**: Uses the spread operator (`...`), which also creates a new array by copying elements from the original array. **Pros and Cons** * **Slice**: + Pros: Widely supported in modern browsers, relatively simple implementation. + Cons: Can be slower than the spread operator for very large arrays due to its extra overhead. * **Spread**: + Pros: Can be faster than `.slice()` for large arrays, as it only copies references to the original array elements. + Cons: Less widely supported in older browsers and requires modern JavaScript syntax. **Other Considerations** The benchmark also considers the following factors: * **Browser**: The results are reported for Chrome 103 on Windows Desktop. * **Device Platform**: The test is run on a desktop device, which may affect performance due to differences in hardware or operating system configuration. * **Execution Per Second**: This metric measures how many times each test case can execute in one second. **Library and Special JS Features** In this benchmark, no libraries are used. However, it's worth noting that the spread operator is a modern JavaScript feature introduced in ECMAScript 2015 (ES6). While most modern browsers support it, older browsers may not. If you're interested in exploring alternative approaches or considering factors like performance and browser support for your own projects, here are some additional alternatives: * **Array.prototype.copyWithin()**: This method creates a shallow copy of a portion of an array, which might be faster than `.slice()` for specific use cases. * **`JSON.parse(JSON.stringify(originalArray))`: This approach creates a deep copy of the original array by parsing its JSON representation and then recreating it. However, this is generally slower and less efficient due to the overhead of parsing and reconstruction. Keep in mind that performance differences between these methods can vary depending on the specific use case, data size, and browser configuration. It's essential to consider your project's requirements and choose the approach that best fits your needs.
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