Benchmark: Spread vs Push1 - MeasureThat.net

Tests:

Spread Operator
let arr1 = Array.from({length:1000}).map((_,i)=>i); let arr2 = Array.from({length:1000}).map((_,i)=>i); arr1 = [...arr1,...arr2]
Push with Spread
let arr1 = Array.from({length:1000}).map((_,i)=>i); let arr2 = Array.from({length:1000}).map((_,i)=>i); arr2.forEach(e=>{arr1.push(e)})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread Operator
Push with Spread

Fastest: N/A

Slowest: N/A

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/124.0.0.0 Safari/537.36 Edg/124.0.0.0

Browser/OS: Chrome 124 on Windows

View result in a separate tab

Test name	Executions per second
Spread Operator	6242.0 Ops/sec
Push with Spread	6033.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and other considerations.

**Benchmark Definition**

The benchmark definition is a JSON object that provides metadata about the test case, such as its name, description, script preparation code, HTML preparation code, etc. In this case, there are two benchmark definitions:

1. "Spread Operator"
2. "Push with Spread"

These two benchmark definitions represent different approaches to achieving the same goal: creating a new array by concatenating an existing array.

**Test Cases**

The test cases are individual instances of the benchmark definition, which contain the actual code being tested. There are two test cases:

1. **Spread Operator**
```javascript
arr1 = [...arr1,...arr2];
```
This test case creates two arrays `arr1` and `arr2`, populates them with 1000 elements each using `Array.from()`, and then uses the spread operator to concatenate `arr2` into `arr1`.

2. **Push with Spread**
```javascript
arr1.push(...arr2);
```
This test case creates two arrays `arr1` and `arr2`, populates them with 1000 elements each using `Array.from()`, and then uses the spread operator to add all elements of `arr2` to `arr1` using `push()`.

**Comparison**

The benchmark measures the performance difference between these two approaches. The `Spread Operator` approach creates a new array by spreading the elements of another array, while the `Push with Spread` approach adds elements from one array to another without creating a new array.

**Pros and Cons**

* **Spread Operator**
	+ Pros:
		- Creates a new array, which can be more efficient than modifying an existing array.
		- More readable and concise code.
	+ Cons:
		- Requires JavaScript version 13 or later to support the spread operator syntax.
		- Can lead to unnecessary memory allocation if not used carefully.
* **Push with Spread**
	+ Pros:
		- Works in older JavaScript versions that don't support the spread operator.
		- Can be more efficient than creating a new array for large datasets.
	+ Cons:
		- Less readable and more verbose code compared to the spread operator approach.

**Library**

There is no explicit library mentioned in the benchmark definition. However, it's worth noting that `Array.from()` is a method provided by the Array prototype, which is built into JavaScript.

**Special JS Feature/Syntax**

The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) and is widely supported across modern browsers and JavaScript engines. The `push()` method has been available since ES5, so it's not a special feature or syntax.

**Other Alternatives**

Some alternative approaches to concatenating arrays could be:

* Using the `concat()` method:
```javascript
arr1 = arr1.concat(arr2);
```
* Using a loop to append elements from one array to another:
```javascript
for (let i = 0; i < arr2.length; i++) {
  arr1.push(arr2[i]);
}
```
These alternatives may have different performance characteristics and trade-offs compared to the spread operator approach.

In summary, the benchmark is testing the performance difference between using the spread operator versus pushing elements onto an array using the `push()` method. The results provide insight into which approach is more efficient for specific use cases.

Related benchmarks:

Spread vs Push1 (version: 0)

Comparing performance of: Spread Operator vs Push with Spread

Created: 2 years ago by: Guest

Jump to the latest result

Spread Operator

Push with Spread

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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