Benchmark: Array concat vs spread operator vs pushx

Tests:

Array.prototype.concat
var params = [ "hello", true, 7 ]; params = [ ...params, "444"];
spread operator
var params = [ "hello", true, 7 ] params.push("444");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:83.0) Gecko/20100101 Firefox/83.0

Browser/OS: Firefox 83 on Windows

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	6284495.5 Ops/sec
spread operator	67422104.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation.

**Benchmark Overview**

The provided benchmark measures the performance of three approaches to concatenate an array in JavaScript: using the `concat()` method, the spread operator (`...`), and the `push()` method with the `x` variant (not a standard feature).

**Options Compared**

1. **Array.prototype.concat()**: This is the traditional way to concatenate arrays in JavaScript.
2. **Spread Operator (`...`)**: Introduced in ES6, this operator allows you to create a new array by spreading an existing array or an array-like object.
3. **push()` with `x` variant (not standard)**: The problem statement doesn't specify what the `x` variant is, but it's likely an experimental or proprietary method for concatenating arrays.

**Pros and Cons of Each Approach**

1. **Array.prototype.concat()**:
	* Pros: widely supported, easy to use, and well-documented.
	* Cons: can be slow for large arrays due to the creation of a new array object.
2. **Spread Operator (`...`)**:
	* Pros: concise, fast, and efficient for concatenating small to medium-sized arrays.
	* Cons: requires modern browsers that support ES6 syntax (not all versions), and it modifies the original array if used with `params = [...params, '444']`.
3. **push()` with `x` variant**:
	* Since we don't know what this "variant" is, I'll assume it's not a standard feature or has no documentation. This makes it difficult to provide pros and cons.

**Library and Special JS Features**

There are no libraries mentioned in the benchmark definition, but the use of modern syntax (e.g., spread operator) assumes that the test environment supports ES6 features.

No special JavaScript features are mentioned that would require additional explanation.

**Other Alternatives**

For concatenating arrays, other alternatives include:

1. **Array.prototype.push()` with multiple arguments: `params.push('444')`.
2. **Array.prototype.splice()` with an offset and length.
3. **Array.prototype.slice()` followed by concatenation using the spread operator or `concat()`.
4. **Using a custom array concatenation function (not included in this benchmark).**

Keep in mind that the performance of these alternatives may vary depending on the specific use case and environment.

I hope this explanation helps you understand the benchmark!

Related benchmarks:

Array concat vs spread operator vs pushx (version: 0)

Compare the new ES6 spread operator with the traditional concat() method and push

Comparing performance of: Array.prototype.concat vs spread operator

Created: 4 years ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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