Benchmark: concat/includes vs spread

Tests:

concat/includes
let a1 = [0,1,2,3,4,5,6,7,8,9]; const a2 = ['a', 'b', 'c', 'd', 'e', 'f']; if (!a1.includes(a2)) a1 = a1.concat(a2);
spread
let b1 = [0,1,2,3,4,5,6,7,8,9]; const b2 = ['a', 'b', 'c', 'd', 'e', 'f']; b1 = [...b1, ...b2]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat/includes
spread

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36

Browser/OS: Chrome 110 on Windows

View result in a separate tab

Test name	Executions per second
concat/includes	6902837.0 Ops/sec
spread	18448668.0 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 benchmark and its components.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmark, which is a small code snippet designed to test specific aspects of JavaScript performance. In this case, we have two benchmark definitions:

1. `concat/includes`
2. `spread`

Both benchmarks involve comparing different ways to concatenate (join) arrays in JavaScript.

**Options Compared**

In the `concat/includes` benchmark, we see two options being compared:

a. Using `includes()` and then concatenating with `+` or `concat()`.
b. Using spread syntax (`...`) to concatenate the arrays directly.

In the `spread` benchmark, we have only one option:

c. Using spread syntax (`...`) to concatenate the arrays directly.

**Pros and Cons of Each Approach**

### concat/includes

a. Using `includes()`:
	* Pros: Efficient way to check if an element is present in an array.
	* Cons: May incur additional overhead due to the `includes()` method's internal implementation.

b. Using `+` or `concat()`: 
	* Pros: Simple and widely supported.
	* Cons: May lead to slower performance compared to using `includes()` directly, as it involves creating a new string.

c. Using spread syntax (`...`):
	* Pros: Cleaner code, more readable, and often faster due to the compiler optimizations.
	* Cons: Requires support for spread syntax in older browsers or environments.

### Spread

Using spread syntax (`...`) is generally considered a good practice for concatenating arrays in modern JavaScript. It's concise, easy to read, and often faster than other methods.

**Library Usage**

In both benchmarks, there are no explicit library dependencies mentioned. The `includes()` method is part of the standard JavaScript API, while the spread syntax (`...`) is also a built-in feature.

**Special JS Features or Syntax**

There's no special JavaScript feature or syntax explicitly used in these benchmarks. However, it's worth noting that older browsers may not support spread syntax, so if you need to test compatibility across multiple environments, consider using an alternative approach.

**Other Alternatives**

If you need to concatenate arrays differently, here are some alternatives:

* Using `Array.prototype.push()`:
```javascript
let arr = [0, 1];
arr.push(2, 3);
```
* Using `Array.prototype.splice()`:
```javascript
let arr = [0, 1];
arr.splice(1, 0, 2, 3);
```

Keep in mind that these alternatives may not be as efficient or readable as using spread syntax (`...`).

In summary, the provided benchmark tests the performance of two different ways to concatenate arrays: using `includes()` and concatenation methods versus using spread syntax. The `spread` benchmark shows a faster execution rate, likely due to compiler optimizations and better code generation.

Related benchmarks:

concat/includes vs spread (version: 0)

Comparing performance of: concat/includes vs spread

Created: one year ago by: Guest

Jump to the latest result

concat/includes

spread

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):