Benchmark: Concat vs spread testggdfg

Script Preparation code:

var firstList = Array(100).fill(100);
var secondList = Array(100).fill("100");

Tests:

concat
const newList = [].concat(firstList, secondList);
Spread
const newList = [...firstList, ...secondList];
push
const newList = [].push(...firstList, ...secondList)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat
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.

Let's dive into the explanation of the provided benchmark.

**Benchmark Overview**

The benchmark compares three different approaches to concatenate two arrays in JavaScript: using `Array.prototype.concat()`, `Array.prototype.push()` with spread syntax (`...`), and the spread operator itself (similar to `push()` but without modifying the original array).

**Options Compared**

1. **Concatenation using `Array.prototype.concat()`**: This method creates a new array by concatenating two arrays. It has a time complexity of O(n + m), where n and m are the lengths of the input arrays.
2. **Pushing elements onto an array using spread syntax (`...`)**: When using `push()`, you need to provide the arguments to be pushed onto the array using the spread operator (`...`). This method also has a time complexity of O(n + m).
3. **Spread operator (similar to `push()` but without modifying the original array)**: The spread operator creates a new array by spreading its elements into another array. Its time complexity is also O(n + m).

**Pros and Cons**

1. **Concatenation using `Array.prototype.concat()`**:
	* Pros:
		+ Creates a new array, which can be useful if you need to keep the original arrays unchanged.
		+ Can be more predictable for developers who are used to working with `concat()`.
	* Cons:
		+ Creates unnecessary memory allocation, as it creates a new array object.
2. **Pushing elements onto an array using spread syntax (`...`)**:
	* Pros:
		+ Does not create unnecessary memory allocation, as the original array remains unchanged.
	* Cons:
		+ May be less predictable for developers who are used to working with `push()` and spread syntax together.
3. **Spread operator (similar to `push()` but without modifying the original array)**:
	* Pros:
		+ Does not create unnecessary memory allocation, as it does not modify the original array.
	* Cons:
		+ May be less efficient due to the overhead of creating a new array.

**Library Usage**

In this benchmark, none of the test cases use any external libraries. The code is self-contained and only relies on built-in JavaScript features.

**Special JS Features/Syntax**

None of the test cases use any special JavaScript features or syntax beyond what's covered in the standard library. However, it's worth noting that some JavaScript engines may have specific optimizations or quirks that can affect performance, but these are not typically considered part of the standard language.

**Alternatives**

If you're interested in exploring other ways to concatenate arrays, here are a few alternatives:

1. **Using `Array.prototype.slice()`**: This method creates a shallow copy of an array and returns it. You can then concatenate two arrays using this new array.
2. **Using a loop**: You can use a loop to iterate over both input arrays and push elements onto the result array.

Here's some example code for these alternatives:

```javascript
// Using `Array.prototype.slice()`
const newList = Array.from(firstList).concat(Array.from(secondList));

// Using a loop
const newList = [];
for (let i of firstList) {
    newList.push(i);
}
for (let j of secondList) {
    newList.push(j);
}

// (Note: This alternative is not as efficient as using the spread operator or `push()`)
```

Keep in mind that these alternatives may have different performance characteristics and may be less efficient than the original approach used in this benchmark.

Related benchmarks:

Concat vs spread testggdfg (version: 4)

Comparing performance of: concat vs Spread vs push

Created: 5 years ago by: Registered User

Jump to the latest result

concat

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):