Benchmark: Array.prototype.fsd slice vs spread operator copy performance

Tests:

Array.prototype.slice
var params = [ "hello", true, 7 ]; var other = Array.from(params);
spread operator
var params = [ "hello", true, 7 ] 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 one month ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases to understand what is being tested.

**Benchmark Definition:**

The benchmark is comparing the performance of two approaches:

1. **Traditional `slice()` method**: This method returns a shallow copy of a portion of an array, starting from the specified index and ending at the specified end index (inclusive).
2. **New ES6 spread operator (`...`)**: This operator creates a new array containing the elements of the original array.

**Options Compared:**

The benchmark is comparing the performance of these two approaches on creating a shallow copy of an array with three elements: a string, a boolean, and an integer.

**Pros and Cons of Each Approach:**

1. **Traditional `slice()` method**:
	* Pros:
		+ Wide support across different browsers and versions.
		+ Well-established and widely used.
	* Cons:
		+ Returns a shallow copy, which may not be suitable for all use cases (e.g., objects with nested references).
		+ May have performance implications due to the creation of an intermediate array object.
2. **New ES6 spread operator (`...`)**:
	* Pros:
		+ Creates a new array without the need for explicit array methods or intermediate objects.
		+ Generally more efficient, as it avoids the overhead of creating an intermediate array object.
	* Cons:
		+ Less widely supported across different browsers and versions (although improving rapidly).
		+ May not be familiar to all developers.

**Library and Syntax:**

No specific library is used in this benchmark. The `Array.prototype.slice()` method is a built-in JavaScript method, while the spread operator (`...`) is part of the ECMAScript standard since ES6.

**Special JS Feature or Syntax:**

The use of the spread operator (`...`), which was introduced in ES6, is a special syntax that allows for more concise and expressive array creation. This feature is not universally supported across all browsers, but its usage is becoming increasingly common.

**Other Alternatives:**

For creating shallow copies of arrays, other alternatives include:

1. **`Array.prototype.slice()` with a spread operator**: While this approach may seem counterintuitive, some developers use it as a shorthand for `Array.prototype.slice().slice()`. However, this approach still creates an intermediate array object.
2. **`Array.prototype.concat()`**: This method concatenates multiple arrays into one. Although not specifically designed for shallow copying, it can be used in certain situations.
3. **Third-party libraries or utility functions**: For specific use cases or performance-critical applications, developers might opt for custom libraries or utility functions that offer optimized array creation and manipulation.

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

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:101.0) Gecko/20100101 Firefox/101.0

Browser/OS: Firefox 101 on Linux

View result in a separate tab

Test name	Executions per second
Array.prototype.slice	7539995.5 Ops/sec
spread operator	16325316.0 Ops/sec

Related benchmarks:

Array.prototype.fsd slice vs spread operator copy performance (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>

Experimental features:

Fastest: N/A

Slowest: N/A

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