Benchmark: concat vs spread stovt

Script Preparation code:

var array1 = ['2', '3', '4'];
var array2 = ['2', '3', '4'];

Tests:

var array3 = array1.concat(array2);
var array3 = array1.concat(array2);
var array3 = [...array1, ...array2];
var array3 = [...array1, ...array2];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
var array3 = array1.concat(array2);
var array3 = [...array1, ...array2];

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36

Browser/OS: Chrome 111 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
var array3 = array1.concat(array2);	7663054.5 Ops/sec
var array3 = [...array1, ...array2];	10765775.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data to understand what is being tested in this JavaScript microbenchmark.

**Benchmark Definition**

The benchmark tests two approaches for concatenating arrays: using the `concat()` method and using the spread operator (`...`).

**Options Compared**

The two options being compared are:

1. **`array1.concat(array2)`**: This approach uses the `concat()` method, which appends one or more arrays to another array.
2. **`[...array1, ...array2]`**: This approach uses the spread operator (`...`) to concatenate two arrays.

**Pros and Cons of Each Approach**

* **`concat()` method:**
	+ Pros:
		- Widely supported across different browsers and Node.js versions.
		- Can handle large arrays efficiently.
	+ Cons:
		- May be slower for very large arrays due to the overhead of creating a new array.
		- Requires more memory allocations than the spread operator approach.
* **Spread Operator (`...`):**
	+ Pros:
		- Often faster and more efficient, especially for small to medium-sized arrays.
		- Creates a new array without the overhead of `concat()` method.
	+ Cons:
		- Less widely supported across older browsers and Node.js versions.
		- May not work as expected with very large arrays due to memory constraints.

**Library Usage**

There is no explicit library usage in this benchmark. However, the spread operator approach uses the `Array.prototype.push()` method internally, which is a part of the JavaScript language standard. The `concat()` method also uses `Array.prototype.concat()`, which is also part of the standard.

**Special JS Features or Syntax**

The benchmark does not use any special JavaScript features or syntax that would require additional explanation. It only tests the basic array concatenation methods provided by the JavaScript language standard.

**Other Alternatives**

If you want to compare other array concatenation approaches, here are some alternatives:

1. **Using `Array.prototype.reduce()`**: This method can be used to concatenate arrays in a more functional programming style.
2. **Using `Array.prototype.join()` with a separator**: While not strictly an array concatenation approach, this method can be used to concatenate strings or values using a separator.

For example, the benchmark could include additional test cases for these alternative approaches:

```json
{
    "Benchmark Definition": "var result = array1.reduce((acc, val) => acc.concat(val));",
    ...
}
```

Or,

```json
{
    "Benchmark Definition": "var result = array1.join('');",
    ...
}
```

Note that these alternatives may not be as efficient or widely supported as the original `concat()` and spread operator approaches.

Related benchmarks:

concat vs spread stovt (version: 0)

Comparing performance of: var array3 = array1.concat(array2); vs var array3 = [...array1, ...array2];

Created: one year ago by: Guest

Jump to the latest result

var array3 = array1.concat(array2);

var array3 = [...array1, ...array2];

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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