Benchmark: spread vs forEach push v4

Script Preparation code:

var arr = Array.from(Array(1000).keys())

Tests:

spread
var brr = []; brr.push(...arr);
forEach push
var drr = []; arr.forEach(item => { drr.push(item); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
forEach push

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 123 on Android

View result in a separate tab

Test name	Executions per second
spread	396459.0 Ops/sec
forEach push	215115.3 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases for you.

**Benchmark Definition:**

The benchmark definition is a JSON object that describes two different approaches to adding elements to an array:

1. `var brr = [];` (initializing an empty array)
2. `arr.forEach(item => {\r\n\tdrr.push(item);\r\n});` (using the `forEach` method)

The purpose of this benchmark is to compare the performance of these two approaches when adding elements to an array.

**Options Compared:**

Two options are compared:

1. **Spread Operator (`...`)**: used in the line `brr.push(...arr);`
2. **forEach Method**: used in the line `arr.forEach(item => {\r\n\tdrr.push(item);\r\n});`

**Pros and Cons of Each Approach:**

1. **Spread Operator (`...`)**:
	* Pros:
		+ Can be more readable and concise, especially for small arrays.
		+ Allows for easy iteration over arrays using `for...of`.
	* Cons:
		+ May have performance overhead due to the need to create a new array.
2. **forEach Method**:
	* Pros:
		+ Can be used with other methods that modify the array, such as `map` and `filter`.
		+ Allows for callback functions to perform custom operations on each element.
	* Cons:
		+ May have performance overhead due to the need to iterate over the entire array.

**Library/Functionality Used:**

None explicitly mentioned in this benchmark. However, `Array.from()` is used to create an initial array, which is then passed as an argument to the spread operator or used with `forEach`.

**Special JS Feature/Syntax:**

* **Spread Operator (`...`)**: Introduced in ECMAScript 2015 (ES6), it allows for element-wise expansion of arrays.
* **forEach Method**: Introduced in ECMAScript 1999 (ECMAScript 3), it allows iteration over arrays using a callback function.

**Other Alternatives:**

If you want to explore other approaches, here are some alternatives:

1. `arr.concat()`: Concatenates the array with the elements from the provided iterable.
2. `Array.prototype.push.apply(arr, arr)`: A more explicit way of pushing all elements from an array onto another array.
3. `for...of loop` without using `forEach`: You can use a traditional `for` loop to iterate over arrays.

Here's an example implementation:
```javascript
let brr = [];
for (let item of arr) {
  brr.push(item);
}
```
Keep in mind that the performance differences between these approaches may not be significant for small arrays, but they can become noticeable as the array size increases.

Related benchmarks:

spread vs forEach push v4 (version: 0)

Comparing performance of: spread vs forEach push

Created: 2 years ago by: Guest

Jump to the latest result

spread

forEach push

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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