Benchmark: Array.prototype.concat vs spread operator (2 separate arrays of same type)

Tests:

Array.prototype.concat
const params = [ {id:1}, {id:2}, {id:3} ]; const initial = [ {id:4}, {id:5}, {id:6} ]; const other = initial.concat(params);
spread operator
const params = [ {id:1}, {id:2}, {id:3} ]; const initial = [ {id:4}, {id:5}, {id:6} ]; const other = [ ...initial, ...params ]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:124.0) Gecko/20100101 Firefox/124.0

Browser/OS: Firefox 124 on Linux

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	8935132.0 Ops/sec
spread operator	6256677.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**Benchmark Definition**

The benchmark is designed to compare two approaches for concatenating arrays in JavaScript: the traditional `concat()` method and the ES6 spread operator (`...`).

**Options Compared**

The benchmark compares two options:

1. **Traditional `concat()` method**: This approach uses the `concat()` function to concatenate two arrays.
```javascript
const other = initial.concat(params);
```
2. **ES6 spread operator**: This approach uses the spread operator (`...`) to concatenate two arrays.
```javascript
const other = [ ...initial, ...params ];
```
**Pros and Cons**

**Traditional `concat()` method:**

Pros:

* Well-established and widely supported in older browsers.
* Easy to understand and implement.

Cons:

* Can be slow for large arrays due to the overhead of creating new array objects.
* Can lead to unnecessary memory allocation.

**ES6 spread operator:**

Pros:

* Fast and efficient, as it avoids creating new array objects.
* Modern and widely supported in recent browsers.

Cons:

* May require explicit knowledge of the spread operator syntax.
* Not well-established in older browsers.

**Library and Purpose**

In the provided benchmark, there is no specific library being used. The code examples use built-in JavaScript features (i.e., `concat()` and the spread operator).

**Special JS Features or Syntax**

The benchmark uses ES6 features, specifically:

1. **Spread operator (`...`)**: Introduced in ECMAScript 2015 as a new way to concatenate arrays.
2. **Template literals**: Used for string interpolation in the script preparation code.

Other considerations:

* The benchmark focuses on measuring the performance difference between two specific approaches, rather than exploring other optimizations or edge cases.
* The use of `null` values for `Script Preparation Code` and `Html Preparation Code` suggests that the benchmark might be using a minimal setup to test the array concatenation performance in isolation.

**Other Alternatives**

If you were to explore alternative approaches to concatenate arrays, some options could include:

1. **Array.prototype.push()**: Using `push()` method to add elements to an existing array.
```javascript
const other = initial;
other.push(...params);
```
2. **Set**: Using a Set data structure to avoid duplicates and improve performance for large datasets.
```javascript
const other = new Set(params).size > 0 ? params : [];
```
However, these alternatives might have different performance characteristics, trade-offs in terms of memory usage or complexity, and may not be as straightforward to implement as the traditional `concat()` method or ES6 spread operator.

Related benchmarks:

Array.prototype.concat vs spread operator (2 separate arrays of same type) (version: 0)

Compare the ES6 spread operator with the traditional concat() method

Comparing performance of: Array.prototype.concat vs spread operator

Created: 2 years ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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