Benchmark: Spread vs Concat

Tests:

Spread
arr1 = [1, 2, 4] arr2 = ['a', 'b', 'c'] arr3 = [...arr1, ...arr2]
Concat
arr1 = [1, 2, 4] arr2 = ['a', 'b', 'c'] arr3 = arr1.concat(arr2)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread
Concat

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated 29 days ago):

LLMs can make mistakes. Check important info.

This benchmark compares two methods for concatenating arrays in JavaScript: the spread operator (`...`) and the `concat()` method.

**Here's a breakdown:**

* **Spread Operator (`...`)**: This approach uses the spread operator to expand the elements of `arr1` and `arr2` into a new array `arr3`.  
   *  **Pros**: Generally considered more concise and readable. Often performs better in modern JavaScript engines due to optimizations.
   * **Cons**: Can potentially create unnecessary intermediate arrays depending on the engine implementation.

* **`concat()` Method**: This method takes one or more arrays as arguments and returns a new array containing all the elements from the input arrays. 
   *  **Pros**: Well-established and familiar to many developers. Works reliably across different JavaScript environments.
   * **Cons**: Can be more verbose than the spread operator. Performance may not be as optimized in some cases.

**Alternatives:**

While `concat()` and the spread operator are common, there are other ways to achieve array concatenation:

* **Array literals**: Manually listing elements within square brackets (`[1, 2, 4, 'a', 'b', 'c']`). This is simple for small arrays but can become cumbersome for larger ones.
* **`push()` Method**:  You can use `push()` to add elements to the end of an existing array. This is efficient for adding individual elements, but not ideal for concatenating multiple arrays at once.

**Important Notes:**

* The benchmark results you provided show that the spread operator (`...`) was slightly faster in this particular test case. However, performance can vary depending on factors like the size of the arrays, the JavaScript engine being used, and other code running concurrently.
* It's crucial to remember that benchmarks should be interpreted with caution. They provide a snapshot of performance under specific conditions and may not always reflect real-world usage scenarios. Always consider factors beyond raw speed, such as readability and maintainability.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

Browser/OS: Chrome 65 on Linux

View result in a separate tab

Test name	Executions per second
Spread	475763.1 Ops/sec
Concat	574971.3 Ops/sec

Related benchmarks:

Spread vs Concat (version: 0)

Comparing performance of: Spread vs Concat

Created: 6 years ago by: Guest

Jump to the latest result

Spread

Concat

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated 29 days ago):