Benchmark: Array.prototype.concat vs ES6 spread operator

Tests:

Array.prototype.concat
var params = [ "hello", true, 7 ]; var other = [ 1, 2 ].concat(params);
ES6 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
ES6 spread operator

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:75.0) Gecko/20100101 Firefox/75.0

Browser/OS: Firefox 75 on Ubuntu

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	9914215.0 Ops/sec
ES6 spread operator	7743666.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the provided benchmark and explain what's being tested.

The benchmark is comparing two approaches to concatenate arrays in JavaScript:

1. `Array.prototype.concat()`: This method takes two or more arrays as arguments and returns a new array that contains all the elements from each argument.
2. The ES6 spread operator (`...`): This syntax allows you to expand an array into individual elements, making it easier to merge multiple arrays.

**Options Compared**

The benchmark is comparing the performance of these two approaches in terms of execution time, specifically for a simple concatenation operation. The test cases are designed to isolate the differences between the two methods.

**Pros and Cons**

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

Pros:

* Well-established method with good browser support.
* Easy to understand and use.

Cons:

* Can be slower than the ES6 spread operator due to its iterative nature.

**ES6 Spread Operator (`...`)**

Pros:

* More concise and readable syntax.
* Can lead to better performance in some cases due to its ability to avoid creating intermediate arrays.

Cons:

* May not work as expected in older browsers or environments that don't support the ES6 spread operator.

**Library Usage**

There is no explicit library usage mentioned in the benchmark definition. However, it's worth noting that the test cases use a simple array concatenation operation, which doesn't rely on any external libraries.

**Special JS Feature or Syntax**

The ES6 spread operator (`...`) is a special feature introduced in ECMAScript 2015 (ES6). It allows you to expand an array into individual elements, making it easier to merge multiple arrays. This syntax is widely supported in modern browsers and JavaScript environments.

**Other Alternatives**

In addition to `Array.prototype.concat()` and the ES6 spread operator, there are other ways to concatenate arrays in JavaScript:

* Using the `+` operator: `var arr = [1, 2]; var newArr = arr + [3, 4];`. This method is slower than using `concat()`, but it's a simple alternative.
* Using `Array.prototype.push()` and initializing an empty array: `var arr = []; arr.push(1); arr.push(2);`. This method can be slower due to the overhead of pushing elements onto the array.

However, these alternatives are not directly comparable to the ES6 spread operator in terms of performance.

Related benchmarks:

Array.prototype.concat vs ES6 spread operator (version: 0)

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

Comparing performance of: Array.prototype.concat vs ES6 spread operator

Created: 4 years ago by: Registered User

Jump to the latest result

Array.prototype.concat

ES6 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):