Benchmark: array concat w/ spread operator vs push

Tests:

concat with spread
var params = [ "hello", true, 7 ]; var other = [].concat(...params, 'hi');
push
var params = [ "hello", true, 7 ]; var other = params.push('hi');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat with spread
push

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) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36

Browser/OS: Chrome 85 on Windows

View result in a separate tab

Test name	Executions per second
concat with spread	2150949.2 Ops/sec
push	32948720.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared options, pros and cons, and other considerations.

**What is being tested?**

The benchmark compares two approaches to concatenate an array with a string:

1. Using the spread operator (`...`): `var other = [].concat(...params, 'hi');`
2. Using the `push()` method: `var other = params.push('hi');`

The test cases use a simple example with an array of strings and numbers: `[ "hello", true, 7 ]`.

**Options compared**

Two approaches are being tested:

1. **Spread operator (`...`)**:
	* Pros:
		+ More concise and expressive syntax.
		+ Can be more efficient in some cases (see [this discussion](https://www.ecma-international.org/publications-and-standards/standards/ecma-262/))).
	* Cons:
		+ May not work as expected if the spread operator is used incorrectly or with a non-array value.
		+ May have performance overhead due to the need for dynamic array creation.
2. **`push()` method**:
	* Pros:
		+ Simple and familiar syntax.
		+ Does not require creating a new array.
	* Cons:
		+ More verbose compared to the spread operator.
		+ Can be less efficient in some cases due to the need for dynamic array resizing.

**Other considerations**

Before deciding between these approaches, consider the following factors:

* **Readability and maintainability**: The spread operator may make the code more concise and easier to read, while the `push()` method may be clearer for developers who are not familiar with it.
* **Performance**: In some cases, the spread operator might have a performance advantage due to its ability to create an array in a single step. However, this depends on various factors, such as the specific use case and browser implementation.
* **Compatibility**: Both approaches work in modern browsers, but older browsers may not support the spread operator.

**Library usage**

In this benchmark, there are no external libraries used other than `Array.prototype.push()` which is a built-in JavaScript method. However, it's worth noting that some libraries like Lodash might provide additional utility functions for array manipulation, including concatenation methods.

**Special JS feature or syntax**

The spread operator (`...`) is a relatively recent addition to the ECMAScript standard and was introduced in ECMAScript 2015 (ES6). It allows expanding an iterable object into individual elements. This feature is widely supported in modern browsers and JavaScript engines, but older browsers might not support it.

In summary, this benchmark compares two approaches for concatenating arrays with strings: using the spread operator (`...`) or the `push()` method. The choice between these approaches depends on factors such as readability, maintainability, performance, and compatibility.

Related benchmarks:

array concat w/ spread operator vs push (version: 0)

Comparing performance of: concat with spread vs push

Created: 4 years ago by: Guest

Jump to the latest result

concat with spread

push

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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