Benchmark: push vs spread svelte

Tests:

push
let a = [9, 6, 7, 3]; a.push(1); a = a;
spread
let a = [9, 6, 7, 3]; a = [...a, 1];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push
spread

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in the provided benchmark and compare the different approaches.

**Benchmark Definition**

The `push` vs `spread` benchmark tests how JavaScript engines perform when using two different ways to add an element to an array:

1. The `push` method: `a.push(1);`
2. The spread operator (`...`) method: `a = [...a, 1];`

**Options Compared**

The benchmark compares the performance of these two approaches in Svelte, a JavaScript framework that aims to provide a simple and efficient way to build web applications.

**Pros and Cons of Each Approach**

* **`push` method**:
	+ Pros: Simple and intuitive syntax.
	+ Cons: Can lead to slower performance due to the need to create a new array object with the `length` property updated.
* **Spread operator (`...`) method**:
	+ Pros: More concise syntax, can be faster since it doesn't require updating the `length` property of an existing array object.
	+ Cons: Less intuitive for some developers, may lead to unexpected behavior if not used carefully.

**Library and Purpose**

In this benchmark, there is no explicit library being tested. However, Svelte's implementation of JavaScript is likely to influence the results.

**Special JS Feature or Syntax**

The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) as a new syntax for creating arrays. It allows you to create a new array by spreading an existing array or other iterable object.

**Other Alternatives**

In addition to `push` and the spread operator, there are other ways to add elements to an array:

* **Using `concat()`**: `a = a.concat(1);`
* **Using `slice()`: `a = a.slice(0, -1).concat(1);`

These alternatives may also be included in future benchmark runs.

**Why Spread Operator Might Be Faster**

The spread operator (`...`) might be faster than the `push` method because it:

1. Creates a new array object with a fixed size.
2. Returns a reference to that new array object, which is then assigned back to `a`.
3. Does not require updating the `length` property of an existing array object.

In contrast, the `push` method involves:

1. Creating a temporary array object with the element being pushed.
2. Updating the `length` property of the original array object.
3. Assigning the temporary array object back to `a`.

This approach can lead to slower performance due to the overhead of updating the `length` property and creating a new temporary array object.

Keep in mind that these are general explanations, and actual performance differences may vary depending on the specific JavaScript engine, browser, and runtime environment being used.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.99 Safari/537.36

Browser/OS: Chrome 97 on Windows

View result in a separate tab

Test name	Executions per second
push	54434096.0 Ops/sec
spread	34693956.0 Ops/sec

Related benchmarks:

push vs spread svelte (version: 0)

Comparing performance of: push vs spread

Created: 5 years ago by: Guest

Jump to the latest result

push

spread

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):