Benchmark: Concat v Spread - MeasureThat.net

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

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36

Browser/OS: Chrome 87 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	8021572.5 Ops/sec
spread operator	30481084.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark compares two approaches to concatenate arrays: the traditional `concat()` method and the new ES6 spread operator (`...`). The benchmark is designed to measure which approach performs better in terms of execution speed.

**Options Compared**

There are two options compared:

1. **Traditional `concat()` method**: This method takes multiple arrays as arguments and returns a new array containing all the elements from each input array.
2. **New ES6 spread operator (`...`)**: This syntax allows you to extract a subset of elements from an array and assign them to a new array.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Traditional `concat()` method**:
	+ Pros:
		- Wide support across older browsers
		- Easy to read and understand for developers familiar with the traditional syntax
	+ Cons:
		- Can be slower than the spread operator due to the need to create a new array and iterate over each input array
* **New ES6 spread operator (`...`)**:
	+ Pros:
		- Faster execution time, especially when dealing with large arrays
		- More concise and readable code
	+ Cons:
		- Requires support for modern browsers and JavaScript engines

**Library/ Framework**

There is no specific library or framework being used in this benchmark. The script preparation code and HTML preparation code are empty, which means that the test cases only rely on built-in JavaScript features.

**Special JS Feature/Syntax**

The spread operator (`...`) is a new feature introduced in ES6 (ECMAScript 2015). It allows you to extract a subset of elements from an array and assign them to a new array. This syntax is supported by modern browsers, but may not work in older browsers.

**Other Alternatives**

There are other ways to concatenate arrays in JavaScript, such as using `Array.prototype.push()` or `Array.prototype.splice()`. However, these methods are less concise and readable than the spread operator or traditional `concat()` method. Another alternative is using `Array.prototype.slice()` followed by concatenation with `+`, but this approach also has performance overhead compared to the spread operator.

Here's an example of how you can use `Array.prototype.push()` to concatenate arrays:

```javascript
var other = [];
other.push(1, 2);
other.push(...params);
```

And here's an example using `Array.prototype.slice()` followed by concatenation with `+`:

```javascript
var other = [];
other = other.concat(params.slice());
```

In contrast, the spread operator and traditional `concat()` method are more concise and readable ways to concatenate arrays.

Overall, the benchmark is designed to measure the performance difference between two approaches to concatenating arrays in JavaScript. The results suggest that the new ES6 spread operator is faster than the traditional `concat()` method.

Related benchmarks:

Concat v Spread (version: 0)

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

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

Created: 4 years 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 2 months ago):