Benchmark: Array.prototype.slice vs spread operator 2D

Tests:

Array.prototype.slice
var params = [ [1, 2], [3, 4], [5, 6], [7, 8], [9, 10] ]; var ans = []; for (let i = 0; i < params.length; i++) { ans.push(params[i].slice()); }
spread operator
var params = [ [1, 2], [3, 4], [5, 6], [7, 8], [9, 10] ]; var ans = []; for (let i = 0; i < params.length; i++) { ans.push([...params[i]]); }

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: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36

Browser/OS: Chrome 128 on Windows

View result in a separate tab

Test name	Executions per second
Array.prototype.slice	14503165.0 Ops/sec
spread operator	11133719.0 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 benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is designed to compare two approaches for creating a new array with data from an existing 2D array:

1. **Array.prototype.slice**: The traditional method of using `slice()` to extract a subset of elements from an array.
2. **Spread Operator (`...`)**: The new ES6 spread operator, introduced in ECMAScript 2015, which allows creating a new array by spreading the elements of another array.

**Options Compared**

The benchmark is comparing two options:

1. **Array.prototype.slice**: This method creates a shallow copy of the specified range of elements from an array.
2. **Spread Operator (`...`)**: This operator creates a new array by spreading the elements of another array.

**Pros and Cons**

* **Array.prototype.slice**:
	+ Pros:
		- Well-established and widely supported
		- Generally faster for small to medium-sized arrays
	+ Cons:
		- Can be slower for large arrays due to the overhead of creating a new array
		- May not work as expected with sparse arrays or arrays with non-contiguous indices
* **Spread Operator (`...`)**:
	+ Pros:
		- More concise and readable than `slice()`
		- Generally faster for large arrays, since it avoids creating an intermediate array
	+ Cons:
		- May not work as expected with certain types of data (e.g., non-array values)
		- Requires support for ES6 spread operator syntax

**Library**

There is no external library used in this benchmark. Both `Array.prototype.slice` and the spread operator are built-in JavaScript features.

**Special JS Feature or Syntax**

The spread operator (`...`) is a new feature introduced in ECMAScript 2015. It's not yet widely supported in older browsers, so it's likely that Chrome 128 is one of the few browsers that supports it.

In summary, this benchmark is designed to compare the performance of two approaches for creating a new array with data from an existing 2D array: `Array.prototype.slice` and the spread operator (`...`). The benchmark is interested in understanding which approach is faster and more efficient for large datasets.

**Other Alternatives**

If you want to create a new array by spreading elements from another array, you can use other methods, such as:

* Using `Array.from()` with an iterable: `Array.from([1, 2], () => [3, 4])`
* Using `map()` and `concat()`: `[].concat(...[1, 2].map(() => [3, 4]))`

However, these methods may not be as efficient as the spread operator for large datasets.

Related benchmarks:

Array.prototype.slice vs spread operator 2D (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>

Fastest: N/A

Slowest: N/A

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