Benchmark: Spread Push VS Concat Reassign

Script Preparation code:

var data = [
  1, 2, 3, 4,
  [1, 2, 3, 4],
  5, 6, 7, 8,
  [1, 2, 3, 4]
];

Tests:

Spread Push
(function fn(items){ var result = []; items.forEach(item => { if(item.pop) { result.push(...fn(item)); } else { result.push(item); } }); return result; })(data);
Concat Reassign
(function fn(items){ var result = []; items.forEach(item => { if(item.pop) { result = result.concat(fn(item)); } else { result.push(item); } }); return result; })(data);
Apply Push
(function fn(items){ var result = []; items.forEach(item => { if(item.pop) { result.push.apply(result, fn(item)); } else { result.push(item); } }); return result; })(data);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread Push
Concat Reassign
Apply Push

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark for you.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark named "Spread Push VS Concat Reassign". The benchmark compares three different approaches to push elements into an array: using `Array.prototype.push()` with the spread operator (`...`), `Array.prototype.concat()`, and `Array.prototype.push.apply()`. Each approach is applied to the same test data, which includes nested arrays.

**Test Cases**

There are three individual test cases:

1. **Spread Push**: This test case uses the spread operator (`...`) to push elements into an array.
```javascript
items.forEach(item => {
  if (item.pop) {
    result.push(...fn(item));
  } else {
    result.push(item);
  }
});
```
2. **Concat Reassign**: This test case uses `Array.prototype.concat()` to reassign the result array with new elements pushed by the recursive call `fn(item)`.
```javascript
items.forEach(item => {
  if (item.pop) {
    result = result.concat(fn(item));
  } else {
    result.push(item);
  }
});
```
3. **Apply Push**: This test case uses `Array.prototype.push.apply()` to push elements into an array.
```javascript
items.forEach(item => {
  if (item.pop) {
    result.push.apply(result, fn(item));
  } else {
    result.push(item);
  }
});
```
**Library Used**

None of the test cases explicitly use a JavaScript library. However, it's worth noting that `Array.prototype` is a built-in JavaScript API.

**Special JS Features/Syntax**

The benchmark uses several features and syntax:

* Spread operator (`...`)
* Rest parameters (`...fn(item)`)
* Function expressions (e.g., `fn(item)`)
* Array methods (e.g., `forEach`, `push`, `concat`)

**Pros and Cons of Each Approach**

Here's a brief summary of the pros and cons of each approach:

1. **Spread Push**
	* Pros:
		+ Efficient for large arrays with many elements
		+ Can be faster due to fewer method calls
	* Cons:
		+ May lead to unexpected behavior if not used carefully (e.g., modifying the original array)
2. **Concat Reassign**
	* Pros:
		+ Easy to understand and implement
		+ Works well with nested arrays
	* Cons:
		+ Can be slower due to repeated method calls
		+ May lead to performance issues if not implemented carefully
3. **Apply Push**
	* Pros:
		+ Efficient for large arrays with many elements
		+ Similar to Spread Push, but with a more traditional approach
	* Cons:
		+ May be less intuitive than Spread Push or Concat Reassign

**Other Alternatives**

For this specific benchmark, there aren't many alternative approaches that would change the fundamental comparison between Spread Push and the other two methods. However, if you were to explore other ways to push elements into an array, some alternatives could include:

* Using a for loop with index arithmetic
* Using `Array.prototype.set()`
* Using a library like Lodash's `_.push()` method

Keep in mind that these alternative approaches might not be as efficient or intuitive as the original three methods.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.122 Safari/537.36

Browser/OS: Chrome 80 on Mac OS X 10.15.3

View result in a separate tab

Test name	Executions per second
Spread Push	3586215.2 Ops/sec
Concat Reassign	1724044.4 Ops/sec
Apply Push	3462351.0 Ops/sec

Related benchmarks:

Spread Push VS Concat Reassign (version: 0)

Comparing performance of: Spread Push vs Concat Reassign vs Apply Push

Created: 8 years ago by: Guest

Jump to the latest result

Spread Push

Concat Reassign

Apply Push

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):