Benchmark: Array.prototype.slice vs spread operator for number only array

Script Preparation code:

var params = [];
params.push(2)
params.push(3)
params.push(4)

Tests:

Array.prototype.slice
var other = params.slice();
spread operator
var other = [ ...params ]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.slice
spread operator

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

**Benchmark Explanation**

The provided JSON represents a JavaScript microbenchmark that compares the performance of two approaches to create a shallow copy of an array: `Array.prototype.slice()` and the new ES6 spread operator (`...`).

**Approaches Compared**

There are two test cases:

1. **`Array.prototype.slice()`**: This method creates a shallow copy of an array by slicing it from the beginning to the end.
2. **Spread Operator (`...`)**: This operator creates a new array with the elements of the original array.

**Pros and Cons of Each Approach**

* `Array.prototype.slice()`
	+ Pros:
		- Widely supported across different browsers and versions.
		- Can be used to create a shallow copy of an array, which is useful for various tasks, such as iteration or manipulation.
	+ Cons:
		- Creates a new object, which can lead to increased memory usage.
		- May be slower than the spread operator for large arrays due to the overhead of creating a new object and slicing the original array.
* Spread Operator (`...`)
	+ Pros:
		- More concise and expressive than `Array.prototype.slice()`.
		- Can create an exact copy of the original array, including its length and properties.
	+ Cons:
		- Not all browsers support the spread operator, or it may be supported but behave unexpectedly (e.g., due to differences in how objects are created).
		- May lead to increased memory usage for large arrays.

**Library and Special JS Features**

There is no library used in this benchmark. However, note that the `...` spread operator was introduced in ECMAScript 2015 (ES6) as a feature, which means it may not be supported in older browsers or environments.

**Other Alternatives**

Other alternatives to create an array copy include:

1. `Array.from()`: Creates an array from an iterable.
2. `Object.assign()`: Copies the properties of one object to another.
3. `JSON.parse(JSON.stringify())`: Creates a deep copy of an object, but be aware that this method can lead to performance issues for large objects.

In summary, the benchmark compares two approaches to create an array copy: `Array.prototype.slice()` and the spread operator (`...`). The spread operator is more concise and expressive, but may have browser compatibility issues or lead to increased memory usage.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36

Browser/OS: Chrome 85 on Mac OS X 10.15.4

View result in a separate tab

Test name	Executions per second
Array.prototype.slice	9524618.0 Ops/sec
spread operator	9110497.0 Ops/sec

Related benchmarks:

Array.prototype.slice vs spread operator for number only array (version: 0)

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

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

Created: 4 years ago by: Guest

Jump to the latest result

Array.prototype.slice

spread operator

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):