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Spread vs Concat speed
(version: 0)
Comparing performance of:
concat vs spread
Created:
7 years ago
by:
Guest
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Tests:
concat
const x = [1 ,2]; x.concat(3)
spread
const x = [1 ,2]; [...x, 3];
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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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 what's being tested in this JavaScript microbenchmark. **Benchmark Definition** The benchmark is comparing the performance of two approaches: using `concat` and using the spread operator (`[...]`). Both approaches are used to add an element (in this case, the number 3) to an array (`x`) that already contains two elements (1 and 2). **Options Compared** * Using `concat()` method to add an element to an array * Using the spread operator (`[...]`) to create a new array with the original array's elements plus the added element **Pros and Cons of Each Approach:** * **Using `concat()`**: This approach is generally simpler and more straightforward. It has been available in JavaScript for longer, so most developers are familiar with it. However, it creates a new array object every time it's called, which can lead to increased memory allocation and garbage collection overhead. * **Using the spread operator (`[...]`)**: This approach is more concise and expressive. It also avoids creating a new array object on each call, as it returns a new array instance that contains all the elements from the original array plus the added element. However, not all browsers support this syntax, and some older versions of JavaScript engines might optimize it differently. **Library or Special JS Feature:** There is no library being used in this benchmark, but it does utilize the spread operator (`[...]`), which is a relatively modern JavaScript feature introduced in ECMAScript 2015 (ES6). **Other Considerations:** * Performance: The benchmark measures the time taken to execute each approach. * Memory allocation: Both approaches have similar memory overhead, but the spread operator might be more efficient due to reduced memory allocation. **Alternatives:** Some alternatives for adding an element to an array in JavaScript include: * `push()`: This method modifies the original array and adds the new element to its end. While it's not shown in this benchmark, it would likely have similar performance characteristics. * Other libraries or functions (e.g., `Array.prototype.add()`): Some libraries or frameworks might provide additional methods for adding elements to arrays. Overall, the spread operator (`[...]`) is a concise and efficient way to add an element to an array, but its performance might vary depending on the browser and JavaScript engine being used.
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