Benchmark: Spread operator vs. slice

Tests:

Spread operator
var n = []; while(n.length < 1000) { n.push('asdf'); n = [...n]; }
Slice()
var n = []; while(n.length < 1000) { n.push('asdf'); n = n.slice(); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread operator
Slice()

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

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

**What is being tested?**

The benchmark compares two approaches to creating a new array reference: using the spread operator (`[...n]`) versus using the `slice()` method.

**Options compared:**

1. **Spread Operator ( `[...n]` )**: This approach creates a new array by spreading the elements of the existing array `n`. The spread operator is a shorthand way to create a new array from an existing one.
2. **Slice() Method ( `n.slice()` )**: This approach creates a new array by cloning the original array `n` using the `slice()` method.

**Pros and Cons:**

1. **Spread Operator ( `[...n]` )**:
	* Pros:
		+ More concise and readable code
		+ Can be faster for small arrays, as it avoids the overhead of function calls and cloning
	* Cons:
		+ May not be supported in older browsers or Node.js versions
		+ Can be slower for large arrays due to the creation of a new array object
2. **Slice() Method ( `n.slice()` )**:
	* Pros:
		+ Widespread browser and Node.js support
		+ Can be faster for large arrays, as it uses optimized cloning algorithms
	* Cons:
		+ Less concise and readable code compared to the spread operator

**Other Considerations:**

1. **Library usage**: There is no library used in this benchmark.
2. **Special JS feature or syntax**: The benchmark does not use any special JavaScript features or syntax.

**Alternatives:**

If you're looking for alternative approaches, consider:

1. **Array.from() Method ( `Array.from(n)` )**: This method creates a new array by copying the elements of the existing array `n`. It's similar to the spread operator but uses an explicit function call.
2. **Array.prototype.push() and then [...n]**: This approach pushes each element from the original array `n` into a new array, which can be more efficient than using either the slice method or the spread operator.

In summary, the benchmark compares two common approaches to creating a new array reference in JavaScript: the spread operator and the slice() method. The choice between these options depends on your specific use case, performance requirements, and desired level of conciseness and readability.

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:69.0) Gecko/20100101 Firefox/69.0

Browser/OS: Firefox 69 on Mac OS X 10.14

View result in a separate tab

Test name	Executions per second
Spread operator	56.6 Ops/sec
Slice()	112.2 Ops/sec

Related benchmarks:

Spread operator vs. slice (version: 0)

Creating a "new" array reference every time

Comparing performance of: Spread operator vs Slice()

Created: 6 years ago by: Guest

Jump to the latest result

Spread operator

Slice()

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):