Benchmark: Push apply vs push spread vs concat

Script Preparation code:

var a1 = [ "hello", "world", true ];
var a2 = [ 42, false, "universe", { number: 12 } ];

Tests:

Concat
a1.concat(a2);
Push apply
a1.push.apply(a1, a2)
Push spread
a1.push(...a2)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Concat
Push apply
Push spread

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 break down the benchmark and explain what is being tested.

**Benchmark Overview**

The benchmark measures the performance of three different ways to concatenate two arrays in JavaScript: `concat()`, `push.apply()`, and `push(...)` (spread syntax).

**What are we testing?**

We're comparing the execution speed of these three approaches:

1. `concat()`: The `concat()` method creates a new array by concatenating the elements of the original array with the elements of another array.
2. `push.apply()`: This approach uses the `apply()` method to call the `push()` method on an existing array, passing in the elements from another array as arguments.
3. `push(...)` (spread syntax): This is a newer way of concatenating arrays using the spread operator (`...`), which creates a new array by spreading the elements of one array into another.

**Options Compared**

The benchmark compares the performance of these three approaches:

* `concat()`: Creates a new array and copies the elements from both arrays.
* `push.apply()`: Modifies an existing array by adding elements to it using `push()` and then applying the `apply()` method.
* `push(...)` (spread syntax): Creates a new array and adds the elements of one array to another using the spread operator.

**Pros and Cons**

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

1. `concat()`:
	* Pros: Simple, efficient, and well-supported in older browsers.
	* Cons: Creates a new array, which can lead to memory allocation issues for large datasets.
2. `push.apply()`:
	* Pros: Modifies an existing array, reducing memory allocation overhead.
	* Cons: Less efficient due to the use of `apply()`, which adds overhead.
3. `push(...)` (spread syntax):
	* Pros: Fast, efficient, and easy to read, making it a popular choice for modern JavaScript development.
	* Cons: Not supported in older browsers or versions of Internet Explorer.

**Library Usage**

There is no library explicitly mentioned in the benchmark definition, but it's worth noting that some JavaScript engines, like V8 (used by Google Chrome), have optimized implementations of these methods.

**Special JS Features/Syntax**

The benchmark uses the spread operator (`...`) to concatenate arrays, which was introduced in ECMAScript 2015 (ES6). This syntax is supported in modern browsers and versions of Internet Explorer 11 and above.

**Other Alternatives**

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

1. `Array.prototype.reduce()`: You can use `reduce()` to concatenate two arrays by reducing the first array's elements to an accumulator, which is then updated with the second array's elements.
2. `Array.prototype.concat.call()`: This method uses `call()` to call the `concat()` method on an existing array, passing in another array as an argument.

Keep in mind that these alternatives might have different performance characteristics or requirements for usage.

I hope this explanation helps you understand what's being tested in the benchmark!

Related benchmarks:

Push apply vs push spread vs concat (version: 0)

Comparing performance of: Concat vs Push apply vs Push spread

Created: 7 years ago by: Guest

Jump to the latest result

Concat

Push apply

Push spread

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):