Benchmark: Array.prototype.concat vs spread operator (no jQuery)

Tests:

Array.prototype.concat
var params = [ "hello", true, 7 ]; var other = [ 1, 2 ].concat(params);
spread operator
var params = [ "hello", true, 7 ] var other = [ 1, 2, ...params ]

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: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Windows

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	9893768.0 Ops/sec
spread operator	39503772.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the provided benchmark.

**What is being tested?**

The test measures the performance difference between two approaches for concatenating arrays in JavaScript:

1. The traditional `concat()` method
2. The new ES6 spread operator (`...`)

**Options compared**

The benchmark compares the performance of these two approaches under different conditions, but it doesn't explicitly compare other options like using `Array.prototype.push()` or `slice()`. However, we can infer that the test is primarily focused on the performance trade-offs between these two syntaxes.

**Pros and Cons of each approach:**

1. **Traditional `concat()` method:**
	* Pros:
		+ Widely supported and understood.
		+ Can be used for concatenating arrays of any type, not just primitive values.
	* Cons:
		+ Has a higher overhead compared to the spread operator.
		+ May lead to unnecessary allocations of new arrays.
2. **ES6 spread operator (`...`):**
	* Pros:
		+ More concise and readable syntax.
		+ Generally faster than `concat()` for concatenating arrays of primitive values.
	* Cons:
		+ Not supported in older browsers or environments.
		+ May lead to unexpected behavior when used with non-array values.

**Library usage**

There is no specific library mentioned in the benchmark, but it's likely that a standard JavaScript implementation (e.g., V8) is being used. The `Array.prototype.concat()` method and the spread operator are part of the ECMAScript standard.

**Special JS feature or syntax**

The benchmark specifically targets the ES6 spread operator (`...`), which was introduced in ECMAScript 2015 as a new way to concatenate arrays. This syntax allows for more concise and expressive code, making it easier to work with arrays in modern JavaScript applications.

**Other alternatives**

If you're looking for alternative approaches to concatenating arrays, some options include:

* Using `Array.prototype.push()`: This method modifies the original array by adding elements to its end.
* Using `slice()`: This method creates a new array that contains all elements of the original array from a specified start index to an optional end index.

In contrast to `concat()` and the spread operator, these alternatives have different performance characteristics and use cases:

* `push()` can be faster for large arrays, but it modifies the original array.
* `slice()` creates a new array without modifying the original, but it may lead to unnecessary allocations.

Keep in mind that the choice of approach depends on your specific use case, code readability requirements, and performance constraints.

Related benchmarks:

Array.prototype.concat vs spread operator (no jQuery) (version: 0)

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

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

Created: 2 years ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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