Benchmark: Concat vs spread operators

Script Preparation code:


var arr = ['1', '2', '3'];
var arr2 = ['1', '2', '3'];

Tests:

Concat
console.log(arr.concat(arr2))
Spread operator
console.log([...arr,...arr2])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Concat
Spread operator

Fastest: N/A

Slowest: N/A

Latest run results:

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

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

**Benchmark Definition**
The benchmark is testing two different ways to concatenate (join) two arrays in JavaScript: using the `concat` method and using the spread operator (`...`).

**Options Compared**

* **Concat**: Using the `concat` method to join two arrays.
	+ Pros:
		- Well-established, widely supported method.
		- Easy to understand and use.
	+ Cons:
		- May be slower than other methods due to its overhead.
		- Can create a new array object, which may not be desired in all cases (e.g., when working with large datasets).
* **Spread Operator**: Using the spread operator (`...`) to join two arrays.
	+ Pros:
		- Often faster and more efficient than `concat` due to its simplicity.
		- Does not create a new array object, making it more memory-efficient.
	+ Cons:
		- May be less intuitive for some developers who are not familiar with the spread operator.

**Other Considerations**

* Both methods have their use cases. The `concat` method is often preferred when working with older browsers or libraries that don't support the spread operator.
* The benchmark results may indicate which method is preferred in terms of performance, but it's essential to consider the specific requirements and constraints of your project.

**Library: None**

There are no external libraries used in this benchmark.

**Special JavaScript Feature or Syntax: Spread Operator**

The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) as a new syntax for creating arrays from iterables. It allows you to "spread out" the elements of an array into a new array, which can be used as an argument to a function or assigned to a new variable.

In this benchmark, the spread operator is used to join two arrays by creating a new array with all the elements from both arrays.

**Other Alternatives**

If you don't have access to modern JavaScript environments that support the spread operator, you could also use other methods to concatenate arrays, such as:

* Using `Array.prototype.push()`: `arr.push(...arr2)`
* Using `Array.prototype.slice()`: `arr = arr.concat(arr2)`
* Using a library like Lodash (if available)

However, these alternatives may have different performance characteristics and may not be suitable for all use cases.

Related benchmarks:

Concat vs spread operators (version: 0)

Comparing performance of: Concat vs Spread operator

Created: 6 years ago by: Guest

Jump to the latest result

Concat

Spread operator

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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