Benchmark: Array.prototype.slice vs spread operator - large array 100000

Script Preparation code:

var arr = Array.from({length: 10000}, () => Math.random())

Tests:

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

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

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36

Browser/OS: Chrome 144 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.prototype.slice	824755.1 Ops/sec
spread operator	834304.9 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark is designed to compare the performance of two approaches:

1. **Array.prototype.slice()**: A traditional method for creating a shallow copy of an array, which takes an integer argument specifying the number of elements to include in the new array.
2. **Spread operator (`[ ...arr ]`)**: The new ES6 spread operator, introduced in JavaScript 2015, allows you to create a new array from an existing one by using the `...` syntax.

**Options being compared**

The benchmark compares these two approaches on a large array of 100,000 elements. The goal is to determine which method is faster for this specific use case.

**Pros and Cons of each approach:**

* **Array.prototype.slice()**: Pros:
	+ Widely supported and well-established method.
	+ Simple to understand and implement.
* Cons:
	+ May be slower than the spread operator due to its implementation in JavaScript engines.
	+ May cause issues when dealing with large arrays, as it creates a new array object that can lead to memory fragmentation.
* **Spread operator (`[ ...arr ]`)**: Pros:
	+ Introduced in ES6, which means modern browsers and JavaScript engines have optimized support for it.
	+ Can be faster than the slice method due to its optimized implementation.
* Cons:
	+ May not be as widely supported or well-established as the slice method.
	+ Can be slower for very large arrays due to memory allocation.

**Library/dependencies**

There is no library or dependency explicitly mentioned in the benchmark definition, but it's likely that the `Array.from()` function used in the script preparation code is a part of the JavaScript standard library.

**Special JS feature/syntax**

The spread operator (`[ ...arr ]`) introduced in ES6 is a special syntax feature. It allows you to create a new array by iterating over an existing array and including each element from the original array in the new array.

**Other alternatives**

If you want to explore other approaches, here are some alternatives:

1. **Array.prototype.concat()**: Another method for creating a new array, but it may be slower than the slice method or spread operator.
2. **Array.prototype.splice()**: A method that modifies the original array by removing elements from the end and returns an array of removed elements, which can be used to create a new array.
3. **Library functions**: Depending on your specific use case, you might want to explore using library functions like `lodash` or `ramda` that provide optimized implementations for common array operations.

Keep in mind that the choice of method ultimately depends on the specific requirements and constraints of your project.

Related benchmarks:

Array.prototype.slice vs spread operator - large array 100000 (version: 0)

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

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

Created: 2 years ago by: Guest

Jump to the latest result

Array.prototype.slice

spread operator

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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