Benchmark: Arrays: spread operator vs push

Tests:

spread operator
var arr = [1, 2, 3]; var out = [...arr, 4];
push function
var arr = [1, 2, 3]; arr.push(4);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread operator
push function

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:137.0) Gecko/20100101 Firefox/137.0

Browser/OS: Firefox 137 on Linux

View result in a separate tab

Test name	Executions per second
spread operator	34487384.0 Ops/sec
push function	148305088.0 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 Overview**

The benchmark compares two ways to append elements to an array in JavaScript: using the spread operator (`...`) and the `push()` function.

**Options Compared**

1. **Spread Operator**: The spread operator (`...`) is used to create a new array by spreading the elements of an existing array into a new array.
2. **Push Function**: The `push()` function is used to add one or more elements to the end of an array.

**Pros and Cons**

* **Spread Operator:**
	+ Pros:
		- Creates a new array, which can be more efficient than modifying the original array.
		- Less error-prone, as it doesn't involve mutation of the original array.
	+ Cons:
		- Can be slower due to the creation of a new array.
* **Push Function:**
	+ Pros:
		- Faster, as it modifies the existing array without creating a new one.
		- Less memory-intensive.
	+ Cons:
		- Can lead to errors if not used carefully (e.g., modifying the original array instead of the expected array).

**Library and Special JavaScript Features**

There is no library or special JavaScript feature explicitly mentioned in this benchmark.

**Other Considerations**

* The benchmark assumes that the input arrays are large enough to require significant performance differences between the two methods.
* The benchmark results may not reflect real-world scenarios, where code readability, maintainability, and other factors might be more important than performance.

**Alternatives**

If you're looking for alternative ways to append elements to an array, some options include:

1. Using `concat()`: This method creates a new array by concatenating the elements of two or more arrays.
2. Using `set()` (in modern browsers): This method sets the value of a property on a Map object with a specified key and a specified value.

Keep in mind that these alternatives might have different performance characteristics, trade-offs, and use cases compared to the spread operator and push function.

I hope this explanation helps! Let me know if you have any further questions.

Related benchmarks:

Arrays: spread operator vs push (version: 0)

Comparing performance of: spread operator vs push function

Created: 7 years ago by: Guest

Jump to the latest result

spread operator

push function

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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