Benchmark: concat vs push + spread vs spread [v2]

Script Preparation code:

var arr1 = ["what", "is", "this"];
var arr2 = ["this", "is", "a", "test", "hello", "how", "are", "you", "today"];

Tests:

Array.prototype.concat
var result = arr1.concat(arr2);
Push + spread operator
var result = []; result.push(...arr1, ...arr2);
spread operator 2
var result = [arr1, ...arr2]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
Push + spread operator
spread operator 2

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases, explaining what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmarking framework called MeasureThat.net. The benchmark is designed to compare the performance of three approaches for concatenating arrays:

1. `Array.prototype.concat()`
2. Using the spread operator (`...`) in combination with `push()`: `array.push(...arr1, ...arr2)`
3. Using the spread operator (`...`) on its own: `[arr1, ...arr2]`

**Script Preparation Code**

The script preparation code defines two arrays:

* `arr1` contains the strings "what", "is", and "this"
* `arr2` contains a longer sequence of strings

This setup is used to test the concatenation performance of each approach.

**Html Preparation Code**

There is no HTML preparation code provided, which means that the benchmarking process doesn't involve any HTML-related overhead or complexity.

**Individual Test Cases**

Each individual test case represents a single execution of one of the three approaches. The test cases are:

1. **Array.prototype.concat()**: Tests the performance of using `Array.prototype.concat()` to concatenate the two arrays.
2. **Push + spread operator**: Tests the performance of using `push()` with the spread operator (`...`) to concatenate the two arrays.
3. **Spread operator 2**: Tests the performance of using the spread operator (`...`) on its own to concatenate the two arrays.

**Pros and Cons**

Here's a brief analysis of each approach:

1. **Array.prototype.concat()**:
	* Pros: Simple, widely supported, and well-established.
	* Cons: May have higher overhead due to method call and potentially slower execution.
2. **Push + spread operator**:
	* Pros: Combines the benefits of `push()` with the convenience of the spread operator, which can reduce overhead.
	* Cons: May require more CPU cycles for parsing the spread operation, especially for large arrays.
3. **Spread operator 2**:
	* Pros: Directly concatenates the two arrays using the spread operator, potentially reducing overhead.
	* Cons: May not be as widely supported or well-established as other approaches.

**Libraries and Special JS Features**

There are no external libraries used in this benchmark, but the use of the spread operator (`...`) is a modern JavaScript feature that was introduced in ECMAScript 2015 (ES6).

**Other Alternatives**

If you're looking for alternative ways to concatenate arrays in JavaScript, here are a few options:

1. `Array.prototype.reduce()` with the callback function: `arr.concat(arr2).reduce((acc, curr) => acc + curr)`
2. Using `Array.prototype.slice()` and concatenation: `arr.concat(arr2).slice(0, arr2.length)`

Related benchmarks:

concat vs push + spread vs spread [v2] (version: 0)

Comparing performance of: Array.prototype.concat vs Push + spread operator vs spread operator 2

Created: 3 years ago by: Guest

Jump to the latest result

Array.prototype.concat

Push + spread operator

spread operator 2

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):