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Array.concat vs Spread(...)
(version: 0)
Comparing performance of:
Array.conca vs Spread
Created:
3 years ago
by:
Guest
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Tests:
Array.conca
const a = [] const b = []; for(let i = 0; i < 100; ++i) { a[i] = i; b[i] = i; } a.concat(b);
Spread
const a = [] const b = []; for(let i = 0; i < 100; ++i) { a[i] = i; b[i] = i; } [...a, ...b];
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Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
Array.conca
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 what's being tested in the provided JSON. **Benchmark Overview** The benchmark compares two approaches for concatenating arrays: using the `concat()` method and using the spread operator (`...`). **Options Compared** 1. **Array.concat()**: This method creates a new array by copying elements from two or more existing arrays. 2. **Spread Operator (`...`)**: This operator spreads the elements of an array (or other iterable) into a new array. **Pros and Cons of Each Approach** 1. **Array.concat()**: * Pros: Can be used to concatenate multiple arrays, allows for easy merging of data structures. * Cons: Creates a new array, which can lead to increased memory usage, especially when dealing with large datasets. 2. **Spread Operator (`...`)**: * Pros: More concise and expressive than `concat()`, creates a new array with minimal overhead. * Cons: Can be slower than `concat()` for very large datasets, as it involves creating a new array and copying elements. **Library Usage** There is no specific library used in this benchmark. The code uses built-in JavaScript features (Array.prototype.concat() and the spread operator). **Special JS Features/Syntax** There are no special JavaScript features or syntax mentioned in the provided code snippets. **Other Considerations** When choosing between these two approaches, consider the trade-offs: * If you need to concatenate multiple arrays and don't mind creating a new array, `concat()` might be a better choice. * If you prefer a more concise and expressive way of concatenating arrays, or if the data is relatively small, the spread operator might be a better option. **Alternative Approaches** Other ways to concatenate arrays in JavaScript include: 1. Using the `push()` method: `a.push(...b)`. 2. Using the `Set` constructor: `new Set([...a, ...b])`, which creates an array with unique elements. 3. Looping and pushing individual elements: `for (const element of a) { b.push(element); }`. However, these alternatives might have different performance characteristics and use cases compared to the `concat()` method and spread operator. The provided benchmark result shows that Safari 16 on Mac OS X 10.15.7 performs slightly better for `Array.conca` (using `concat()`) than for `Spread`, suggesting that the spread operator might be slower in this specific scenario.
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