Benchmark: spread vs push asfhjasdkflahsdf

Script Preparation code:

var arr = (new Array(50000)).fill(null).map((e, i) => (i));

Tests:

spread
arr = [...arr, null]
push
arr.push(null) arr = arr

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
push

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'll break down the explanation into manageable parts.

**Benchmark Overview**

The provided benchmark measures the performance difference between two approaches to add null elements to an array in JavaScript: using the spread operator (`...`) and using the `push()` method with a subsequent reassignment of the array.

**Script Preparation Code**

The script preparation code is used to create a large array with 50,000 elements, filled with `null` values. This array will be used as the initial data for both test cases.
```javascript
var arr = (new Array(50000)).fill(null).map((e, i) => (i));
```
**Html Preparation Code**

The html preparation code is not provided in this example.

**Individual Test Cases**

There are two individual test cases:

1. **Spread**: The first test case uses the spread operator to add a `null` element to the end of the array:
```javascript
arr = [...arr, null];
```
2. **Push**: The second test case uses the `push()` method with a subsequent reassignment of the array to add a `null` element:
```javascript
arr.push(null)\r\narr = arr;
```
Note: The `\r\n` is likely an artifact from the original benchmark setup and can be ignored.

**Pros and Cons**

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

* **Spread Operator (**)**
	+ Pros:
		- More concise and expressive
		- Creates a new array, avoiding mutations to the original array
	+ Cons:
		- May incur additional overhead due to array creation
* **Push() with Reassignment**
	+ Pros:
		- Efficiently adds elements to the end of the array without creating a new one
	+ Cons:
		- Mutates the original array, which can lead to unintended side effects

**Library and Special JS Features**

There is no library used in this benchmark.

**Other Considerations**

* **Cache Locality**: The push() approach may exhibit better cache locality due to the sequential nature of pushing elements onto the end of the array.
* **Array Creation Overhead**: The spread operator may incur additional overhead due to the creation of a new array, which can be significant for large datasets.

**Alternative Approaches**

Some alternative approaches could include:

* Using `concat()` instead of the spread operator: `arr = arr.concat(null);`
* Using `slice()` with negative indices: `arr.slice(0, -1).push(null)`
* Using a custom implementation using indexing and element assignment

Keep in mind that these alternatives may have different performance characteristics or trade-offs, which would be worth exploring if you're looking for further optimization.

Related benchmarks:

spread vs push asfhjasdkflahsdf (version: 0)

Comparing performance of: spread vs push

Created: 3 years ago by: Guest

Jump to the latest result

spread

push

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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