Benchmark: Performance Spread1

Script Preparation code:

var x = new Array(100);

for (var i = 0; i < x.length; i++) {
  x[i] = { item : (new Array(100)).fill(Math.floor(Math.random() * i)) };
}



window.top.tests = {aPush:[], aSpread:[]};
window.test = x;
window.cutoff = 5000;

Tests:

push
for (let element of window.test) window.top.tests.aPush.push(...element.item); if (window.top.tests.aPush.length > window.cutoff) { window.top.tests.aPush = []; console.log('reset control'); }
spread
for (let element of window.test) window.top.tests.aSpread = [...window.top.tests.aSpread,...element.item]; if (window.top.tests.aSpread.length > window.cutoff) { window.top.tests.aPush = []; console.log('reset control'); }

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 28 days ago):

LLMs can make mistakes. Check important info.

Measuring performance is an essential part of software development, and having a reliable benchmarking tool like MeasureThat.net is crucial.

Let's break down the provided benchmark definition JSON:

**Benchmark Definition:**

The test creates an array `x` with 100 elements, where each element is another array filled with random numbers. The script then pushes these elements into two arrays: `aPush` and `aSpread`. The goal is to measure the performance difference between pushing and spreading the elements.

**Script Preparation Code:**
```javascript
var x = new Array(100);
for (var i = 0; i < x.length; i++) {
  x[i] = { item: (new Array(100)).fill(Math.floor(Math.random() * i)) };
}
window.top.tests = { aPush: [], aSpread: [] };
window.test = x;
window.cutoff = 5000;
```
This code sets up the test environment by creating the `x` array and initializing the two target arrays.

**Html Preparation Code:**
There is no HTML preparation code provided, which means that this benchmark is running in a Node.js or browser environment without any additional HTML overhead.

Now, let's examine the individual test cases:

**Test Case 1: "push"**

```javascript
for (let element of window.test) window.top.tests.aPush.push(...element.item);
if (window.top.tests.aPush.length > window.cutoff) { window.top.tests.aPush = []; console.log('reset control'); }
```
This test pushes each `item` array into the `aPush` array using the spread operator (`...`). If the length of `aPush` exceeds the cutoff value, it resets the array.

**Pros:**

* Simple and efficient way to push elements.
* Good for small arrays.

**Cons:**

* Can be slow for large arrays due to the overhead of spreading each element.

**Test Case 2: "spread"**

```javascript
for (let element of window.test) window.top.tests.aSpread = [...window.top.tests.aSpread, ...element.item];
if (window.top.tests.aSpread.length > window.cutoff) { window.top.tests.aPush = []; console.log('reset control'); }
```
This test spreads each `item` array into the `aSpread` array using the spread operator (`...`). If the length of `aSpread` exceeds the cutoff value, it resets the array.

**Pros:**

* More efficient than pushing for large arrays since it avoids creating intermediate arrays.
* Suitable for large arrays.

**Cons:**

* Can be slower than pushing for small arrays due to the overhead of spreading each element.

Now, let's discuss the libraries used in this benchmark:

There is no explicit library mentioned in the script preparation code. However, some internal JavaScript features and APIs are used, such as `window.top.tests` and `window.test`. These are likely part of the browser or Node.js environment.

Some special JS features used here include:

* The spread operator (`...`) which was introduced in ECMAScript 2015.
* The `for...of` loop which is a more concise way to iterate over arrays and objects, introduced in ECMAScript 2015.

**Alternatives:**

If you wanted to implement a similar benchmark using alternative approaches, here are some options:

1. Using `Array.prototype.push()` without the spread operator:
```javascript
for (let element of window.test) {
  let index = 0;
  while (index < element.item.length) {
    window.top.tests.aPush.push(element.item[index]);
    index++;
  }
}
```
This approach is slower than using the spread operator, but can be suitable for small arrays.

2. Using `Array.prototype.concat()` instead of the spread operator:
```javascript
for (let element of window.test) {
  window.top.tests.aSpread = window.top.tests.aSpread.concat(element.item);
}
```
This approach is similar to spreading elements, but creates intermediate arrays, making it less efficient for large arrays.

3. Using a custom implementation without relying on built-in methods:
```javascript
for (let element of window.test) {
  let pushIndex = 0;
  while (pushIndex < element.item.length) {
    window.top.tests.aPush[pushIndex] = element.item[pushIndex];
    pushIndex++;
  }
}
```
This approach is the most manual and least efficient, but can be an interesting exercise for performance enthusiasts.

Latest run results:

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

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 16_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/111.0.5563.72 Mobile/15E148 Safari/604.1

Browser/OS: Chrome Mobile iOS 111 on iOS 16.3

View result in a separate tab

Test name	Executions per second
push	8857.9 Ops/sec
spread	5.9 Ops/sec

Related benchmarks:

Performance Spread1 (version: 0)

Comparing performance of: push vs spread

Created: one year 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 28 days ago):