Benchmark: Array.prototype.concat vs spread operator latest

Tests:

Array.prototype.concat
var params = [ "hello", true, 7 ]; var other = [ 1, 2 ].concat(params);
spread operator
var params = [ "hello", true, 7 ] var other = [ 1, 2, ...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

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and the pros and cons of each approach.

**Benchmark Overview**

The benchmark compares two ways to concatenate arrays in JavaScript:

1. **Array.prototype.concat()**: The traditional method of concatenating arrays using the `concat()` method.
2. **Spread Operator (latest)**: The new ES6 spread operator (`...`) that allows for more concise and expressive array manipulation.

**Test Cases**

There are two test cases:

1. **`Array.prototype.concat`**
	* Test case: `var params = [ "hello", true, 7 ]; var other = [ 1, 2 ].concat(params);`
	* This test case checks how the `concat()` method performs on a small array of primitive values.
2. **`spread operator`**
	* Test case: `var params = [ "hello", true, 7 ]\nvar other = [ 1, 2, ...params ];`
	* This test case checks how the spread operator (`...`) performs when used to concatenate an array with another array.

**Pros and Cons**

**`Array.prototype.concat()`**

Pros:

* Well-established and widely supported method
* Easy to understand and implement

Cons:

* Can be slower than the spread operator for large arrays
* Can create a new object each time, which can lead to memory allocation issues in some cases

**Spread Operator (latest)****

Pros:

* More concise and expressive syntax
* Can be faster than `concat()` for large arrays
* Does not create a new array, instead creates a new iterable

Cons:

* Less widely supported by older browsers or versions of JavaScript
* May lead to confusion due to its non-obvious behavior when used with certain data types (e.g., objects)

**Library Usage**

There is no library mentioned in the provided benchmark. However, it's worth noting that some JavaScript engines may use various internal optimizations or libraries to perform array concatenation. In this case, the benchmark likely assumes that the test cases are designed to isolate these differences.

**Special JS Features or Syntax**

The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) and is a relatively new feature. It allows for more concise and expressive way of creating arrays by spreading existing arrays or values into a new array.

**Other Alternatives**

In addition to `Array.prototype.concat()` and the spread operator, there are other ways to concatenate arrays in JavaScript, such as:

* Using `push()`: `arr.push(...newArr)`
* Using `set()`: `new Set([...arr, ...newArr])`
* Using `reduce()`: `arr.reduce((acc, curr) => [...acc, curr], [])`

These alternatives may have different performance characteristics or use cases, and the benchmark likely aims to compare their performance in specific scenarios.

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/605.1.15 (KHTML, like Gecko) Version/16.2 Safari/605.1.15

Browser/OS: Safari 16 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	12535894.0 Ops/sec
spread operator	186326880.0 Ops/sec

Related benchmarks:

Array.prototype.concat vs spread operator latest (version: 0)

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

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

Created: one year ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

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):