Benchmark: Array.prototype.slice vs spread operator obj

Tests:

Array.prototype.slice
var other = [ { value: 1, id: '12312314' }, {value: 2, id: '341243'}, {value: 3, id: '434667534'} ].slice();
spread operator
var other = [ ...[ { value: 1, id: '12312314' }, {value: 2, id: '341243'}, {value: 3, id: '434667534'} ] ]

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 25 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON benchmark and explain what is being tested, compared, and discussed.

**Benchmark Description**

The benchmark measures the performance difference between two approaches to create a shallow copy of an array in JavaScript:

1. **Array.prototype.slice()**: This method returns a new Array object containing all elements from the original array, starting at the specified index (or the first element if no index is provided).
2. **Spread Operator (ES6)**: Introduced in ECMAScript 2015, the spread operator (`...`) allows creating a new array by spreading the elements of an existing array.

**Comparison**

The benchmark compares these two approaches using identical input data:

* An array with three objects each containing `value` and `id` properties.
* The first approach uses `Array.prototype.slice()` to create a copy of this array.
* The second approach uses the spread operator (`...`) to create a new array by spreading the elements of the original array.

**Pros and Cons**

Here's a brief overview of each approach:

1. **Array.prototype.slice()**:
	* Pros: Widely supported, well-documented, and efficient for creating shallow copies of arrays.
	* Cons: Can be slower than the spread operator for very large arrays due to the overhead of creating an intermediate array.
2. **Spread Operator (ES6)**:
	* Pros: More concise, modern, and expressive way to create new arrays from existing ones.
	* Cons: May have slightly higher overhead compared to `Array.prototype.slice()`, although this difference is usually negligible.

**Library/Features**

No specific JavaScript libraries are mentioned in the benchmark definition. However, it's worth noting that some browsers may optimize or provide additional features for these methods, such as:

* Firefox 116 is using a relatively recent version of Gecko (20100101), which might include performance optimizations for these methods.
* ES6 support is not limited to modern browsers like Chrome or Safari; most major browsers now support it.

**Special JavaScript Features/Syntax**

There's no special JavaScript feature or syntax being used in this benchmark. Both approaches rely on standard language features and don't introduce any advanced concepts like async/await, generators, or closures.

**Other Alternatives**

If you're looking for alternative methods to create shallow copies of arrays, consider:

* **Array.prototype.concat()**: While not as efficient as `Array.prototype.slice()` or the spread operator, it can be useful in certain scenarios.
* **Object.assign()**: Can also be used to create a new array by assigning elements from an existing array.

However, for simple cases like this benchmark, `Array.prototype.slice()` and the spread operator are usually the best choices due to their simplicity, readability, and performance.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/116.0

Browser/OS: Firefox 116 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Array.prototype.slice	12469002.0 Ops/sec
spread operator	9958701.0 Ops/sec

Related benchmarks:

Array.prototype.slice vs spread operator obj (version: 0)

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

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

Created: one year 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 25 days ago):